A Multidirectional Locomotion Light-Driven Soft Crawling Robot

Soft robots based on bionics with multi-freedom and communication abilities have attracted extensive attention in recent years. However, the solutions for soft robots with multidirectional locomotion currently concentrate on complex drive modes and exhibit application unfriendliness. In this work, an untethered multidirectional locomotion light-driven soft crawling robot is proposed with the integration of communication module, which can traverse in four directions with a fixed near-infrared (NIR) light source and is also capable of positioning and perception. Owing to the photothermal response of graphene oxide and ingenious structural design, the critical states of robot deformation can be determined simply by controlling the duration of NIR light, ultimately resulting in different crawling directions. Furthermore, a communication module is integrated into the robot enabling the robot to locate and sense humidity by magnetic coupling. The proposed robot provides an innovative strategy for the design and integration of multidirectional locomotion soft crawling robots, showing great potential in intelligent robots.     

Spiral-Shape Fast-Moving Soft Robots

Soft robots typically exhibit limited agility due to inherent properties of soft materials. The structural design of soft robots is one of the key elements to improve their mobility. Inspired by the Archimedean spiral geometry in nature, here, a fast-moving spiral-shaped soft robot made of a piezoelectric composite with an amorphous piezoelectric vinylidene fluoride film and a layer of copper tape is presented. The soft robot demonstrates a forward locomotion speed of 76 body length per second under the first-order resonance frequency and a backward locomotion speed of 11.26 body length per second at the third-order resonance frequency. Moreover, the multitasking capabilities of the soft robot in slope climbing, step jumping, load carrying, and steering are demonstrated. The soft robot can escape from a relatively confined space without external control and human intervention. An untethered robot with a battery and a flexible circuit (a payload of 1.665 g and a total weight of 1.815 g) can move at an absolute speed of 20 mm s⁻¹ (1 body length per second). This study opens a new generic design paradigm for next-generation fast-moving soft robots that are applicable for multifunctionality at small scales.     

Double-level ball-riding robot balancing: From system design,modeling, controller synthesis,to performance evaluation

In this research, a new robot, double-level ball-riding robot, is introduced. The robot consists of an upper ball-riding subsystem and a lower ball-riding subsystem. The robot’s dynamics model can be considered separately in two identical planes. Euler–Lagrange equation of motion is applied in order to obtain the dynamics model. Motors are included in the robot’s model. The model is then linearized. The robot’s parameters are identified. The robot’s prototype is manufactured and assembled. Linear Quadratic Regulator with Integral (LQR + I) controller is proposed and applied in order to balance both levels of the robot. The complementary and orientation transformation are used to fuse sensors in order to obtain robot leaning angles. Balancing performance of the developed double-level ball-riding robot is evaluated by simulations and experiments. The results show efficient control performance of LQR + I controller.     

Development of the intake system for the SnowEater robot

The development of the intake system for the SnowEater robot is presented in this paper. The SnowEater robot is a small, lightweight and low powered autonomous machine, designed to remove and compact snow from small areas (less than 30 m²). Its design includes four interacting systems to accomplish the task. These systems are the intake, crawler, compressing and navigation system. This paper focuses on the intake system and its cooperative control with the crawler system. The intake system has three screws to collect the snow. The used control encloses the screw alternating motion and the tracked robot motion; the stable autonomous operation under different snow conditions is designed considering the snow income and its processing speed. Furthermore, an altitude mechanism is presented to enhance the mobility in deep snow conditions.     

Jumping like an insect: Design and dynamic optimization of a jumping mini robot based on bio-mimetic inspiration

This paper presents a bio-inspired design of a jumping mini robot including the theoretical analysis on jumping dynamics based on a simplified biological model, the dynamically optimized saltatorial leg design, the overall design of the jumping robot prototype and, as a part of the bio-mimetic research, and the measuring and comparing of the jumping characteristics between the robot and animal. The artificial saltatorial leg is designed to imitate the characteristics of a real jumping insect, kinematically and dynamically, and proposed to reduce the contact force at tarsus–ground interface during jumping acceleration thus optimizes the jumping motion by minimizing the risk of both leg ruptures and tarsus slippage. Then by means of high speed camera experiment, the jumping characteristics of the theoretical jumping model, the jumping insect leafhopper and the robot are compared so as to show the dynamic similarity and optimization results among them. The final energy integrated jumping robot prototype is able to accomplish a movement of continuous jumping, of which a single jumping reaches 100 mm high and 200 mm long, about twice and four times of its body length respectively.     

A predictor for operator input for time-delayed teleoperation

In this paper we describe a method for bridging internet time delays in a free motion type teleoperation scenario in an unmodeled remote environment with video feedback. The method proposed uses minimum jerk motion models to predict the input from the user a time into the future that is equivalent to the round-trip communication delay. The predictions are then used to control a remote robot. Thus, the operator can in effect observe the resulting motion of the remote robot with virtually no time-delay, even in the presence of a delay on the physical communications channel. We present results from a visually guided teleoperated line tracing experiment with 100 ms round-trip delays, where we show that the proposed method makes a significant performance improvement for teleoperation with delays corresponding to intercontinental distances.     

Design and analysis of low-insertion-loss G-band CMOS four-way Wilkinson power dividers and dual balun

We present the design and analysis of G-band CMOS Wilkinson power dividers and dual balun for G-band communication and imaging systems. Miniature spiral and U-shaped four-way Wilkinson power dividers, which are based on three two-way Wilkinson power dividers, are designed and implemented. Miniature spiral dual balun, which is equivalent to an upper balun and a lower balun in parallel, is also designed and implemented for comparison. These devices are planar and symmetrical, and their main structure is implemented by the 2.34-µm-thick topmost metal to minimize the resistive loss. This leads to low insertion loss, and small amplitude imbalance (AI) magnitude and phase difference (PD) deviation. For instance, the spiral four-way Wilkinson power divider occupies 0.033 mm² chip area and achieves S₁₁ of???11.4 dB, S₂₁ of???6.271 dB, S₃₁ of???6.445 dB, S₄₁ of???6.676 dB, and S₅₁ of???6.111 dB at 180 GHz, one of the smallest chip areas and lowest insertion losses for four-way power dividers with similar operation frequency. The corresponding AI magnitude and PD deviation are 0.565 dB and 3.2°, respectively. Moreover, the spiral dual balun occupies 0.026 mm² chip area and achieves S₁₁ of???10.6 dB, S₂₁ of???7.549 dB, S₃₁ of???7.1 dB, S₄₁ of???7.598 dB, and S₅₁ of???7.352 dB at 180 GHz. The corresponding AI magnitude and PD deviation are 0.498 dB and 5.7°, respectively. The prominent results of the spiral and U-shaped four-way Wilkinson power dividers, and the spiral dual balun indicate that they are suitable for power division/combination in G-band systems.

     

An inchworm mobile robot using electromagnetic linear actuator

The capability of motion is one of the important aspects for a micro-robot to fulfill its given tasks. Micro-autonomous systems usually require large force, large displacement and less power consumption. Among different actuation schemes, electromagnetic actuator shows the benefit in a combination of force, displacement and cost effective control. A bristle-based inchworm mobile robot using a short stroke electromagnetic linear actuator is described in the paper. The main body and movable unit of the robot are joined by using a sealed bellows and the bristle legs are designed so that it can operate both on plane surfaces and in liquid. The actuator designed for the robot is a tubular type linear machine with an overall size of Φ7 × 10 mm. The key dimensions of the actuator were determined through magnetic field analysis to achieve optimum force output and necessary travel stroke within the limited space. The predicted actuation force of the actuator is 20 mN and the stroke length is 1.2 mm. Two working prototypes of the actuator were constructed and the performance tests show the effectiveness of the design. A sensorless control scheme with a novel start-up strategy for the designed actuator was developed based on the robotic system modeling and the analyzed results show the satisfactory performance of the system.     

Strong,Compressible, and Ultrafast Self-Recovery Organogel with In Situ Electrical Conductivity Improvement

Coordination complexes are widely used to tune the mechanical behaviors of polymer materials, including tensile strength, stretchability, self-healing, and toughness. However, integrating multivalent functions into one material system via solely coordination complexes is challenging, even using combinations of metal ions and polymer ligands. Herein, a single-step process is described using silver-based coordination complexes as cross-linkers to enable high compressibility (>85%). The resultant organogel displays a high compressive strength (>1 MPa) with a low energy loss coefficient (<0.1 at 50% strain). Remarkably, it demonstrates an instant self-recovery at room temperature with a speed >1200 mm s⁻¹, potentially being utilized for designing high-frequency-responsive soft materials (>100 Hz). Importantly, in situ silver nanoparticles are formed, effectively endowing the organogel with high conductivity (550 S cm⁻¹). Given the synthetic simplification to achieve multi-valued properties in a single material system using metal-based coordination complexes, such organogels hold significant potential for wearable electronics, tissue-device interfaces, and soft robot applications.     

Leveraging Bioinspired Structural Constraints for Tunable and Programmable Snapping Dynamics in High-Speed Soft Actuators

Creating high-speed soft actuators will have broad engineering and technological applications. Snapping provides a power-amplified mechanism to achieve rapid movements in soft actuators that typically show slow movements. However, precise control of snapping dynamics (e.g., speed and direction of launching or jumping) remains a daunting challenge. Here, a bioinspired design principle is presented that harnesses a reconfigurable constraint structure integrated into a photoactive liquid crystal elastomer actuator to enable tunable and programmable control over its snapping dynamics. By reconfiguring constrained fin-array-shaped structure, the snapping dynamics of the structured actuator, such as launching or jumping angle and height, motion speed, and release force can be on-demand tuned, thus enabling controllable catapult motion and programmable jumping. Moreover, the structured actuators exhibit a unique combination of ultrafast moving speed (up to 2.5 m s⁻¹ in launching and 0.22 m s⁻¹ in jumping), powerful ejection (long ejection distance of ≈20 cm, 35 mg ball), and high jumping height (≈8 cm, 40 times body lengths), which few other soft actuators can achieve. This study provides a new universal design paradigm for realizing controllable rapid movements and high-power motions in soft matter, which are useful for building high-performance soft robotics and actuation devices.     

Bioinspired Soft Robotic Caterpillar with Cardiomyocyte Drivers

Biological soft robots have attracted extensive attention and research because of their superiority in executing designed biomedical missions compared with conventional robots. Here, inspired by the crawling mechanism of snakes and caterpillars, a novel biological soft robot composed of asymmetric claws, a carbon nanotube (CNT)‐induced myocardial tissue layer, and a structural color indicator is presented. The asymmetric claws can assist the whole soft robot to accomplish directional movement during the cardiomyocytes' contraction process. The oriented conduct of the CNT layer can regulate the cardiomyocytes' arrangement and improve their beating capability and the contraction performance. However, the structural color indicator provides a visualized monitoring approach to dynamically and immediately reflect the motion status of the biological soft robots. With these three functional layers, the cardiomyocyte‐driven soft robot can greatly simulate the crawling behavior of a caterpillar. It is demonstrated that by integrating these soft robots in a microfluidic organ‐on‐a‐chip system with multitrack construction, they can run along the tracks and exhibit different running speed based on the stimulus concentrations in the tracks. These features indicate the potential values of the cardiomyocyte‐driven soft robots for providing an effective screening platform for clinical diseases.     

A bio-inspired jumping robot: Modeling,simulation, design,and experimental results

This paper presents the design of a jumping robot inspired by jumping locomotion of locusts. The mechanisms of jumping, self-righting, steering, and takeoff angle adjusting are modeled and simulated firstly. Then the 3D model of the robot is designed and a prototype of the robot is fabricated. An eccentric cam with quick return characteristics is used by the jumping mechanism to compress torsion springs for energy storing and to trigger the springs for a quick release of energy. The self-righting, steering, and takeoff angle adjusting capabilities of the robot are achieved by adding a rotatable pole leg. The pole leg can prop up the body of the robot when it falls down. The pole leg can also steer the robot to turn step by step. By adjusting its center of mass (COM) using the pole leg with an additional weight, the robot can jump at different takeoff angles. A 9 cm × 7 cm × 12 cm, 154 g jumping robot prototype is implemented. The fundamental characteristics of the robot are tested. Experimental results show that the constructed robot can jump more than 88 cm high at a takeoff angle of 80.33°. The robot rotates about 277° in the air during jumping. The robot can self-right when it falls down to its left, right, and front sides in 9 s, 9 s, and 26 s respectively. The robot can steer 360° in 42 s with 14 steps, about 25.7° per step. Its takeoff angle ranges between 80.33° and 86.92°. The robot can continuously jump to overcome stairs and jump forward in outdoor environments with self-righting and steering. The experimental results are compared with the simulation results. The differences between them are explained.     

A Fully Self-Healing and Highly Stretchable Liquid-Free Ionic Conductive Elastomer for Soft Ionotronics

Soft ionic conductors hold great potential for soft ionotronics, such as ionic skin, human–machine interface and soft luminescent device. However, most hydrogel and ionogel-based soft ionic conductors suffer from freezing, evaporation and liquid leakage problems, which limit their use in complex environments. Herein, a class of liquid-free ionic conductive elastomers (ICEs) is reported as an alternative soft ionic conductor in soft ionotronics. These liquid-free ICEs offer a combination of desirable properties, including extraordinary stretchability (up to 1913%), toughness (up to 1.08 MJ cm⁻³), Young's modulus (up to 0.67 MPa), rapid fully self-healing capability at room temperature, and good conductivity (up to 1.01 × 10⁻⁵ S cm⁻¹). The application of these ICEs is demonstrated by creating a wearable sensor that can detect and discriminate minimal deformations and human body movements, such as finger or elbow joint flexion, walking, running, etc. In addition, self-healing soft ionotronic devices are demonstrated to confront mechanical breakdown, such as an ionic skin and an alternating-current electroluminescent device that can reuse from damage. It is believed that these liquid-free ICEs hold great promises for applications in wearable devices and soft ionotronics.     

Improving the energy efficiency and speed of walking robots

This study analyses the superior performance of gravitationally decoupled actuation in terms of energy efficiency, and hence autonomy. Based on the decoupling concept, a new design is presented for a 3 dof leg, and its performance is validated by including it in a 84 kg hybrid locomotion robot. The proposed leg obtains a straight-line constant-velocity motion of the foot as only one of its 3 motors is operated at constant speed. This feature, together with the hybrid structure, increases the robot’s efficiency and speed when operating on surfaces without obstacles, and drastically simplifies the walking operation control. A series of simulations have been done comparing the energy consumption of the hybrid robot including traditional coupled legs, and including the proposed decoupled legs. They show a superior performance of the later one. A real prototype has been built including the proposed mechanism. It shows a similar performance to that obtained from simulation, and a natural gait in flat terrains,at speeds up to 0.9 m/s.     

Bio-Inspired Stimuli-Responsive Ti3C2Tx/PNIPAM Anisotropic Hydrogels for High-Performance Actuators

Near-infrared (NIR) light-responsive hydrogels have the advantages of high precision, remote control and excellent biocompatibility, which are widely used in soft biomimetic actuators. The process by which water molecules diffuse can directly affect the deformation of hydrogel. Therefore, it remains a serious challenge to improve the response speed of hydrogel actuator. Herein, an anisotropic photo-responsive conductive hydrogel is designed by a directional freezing method. Due to the anisotropy of the MXene-based PNIPAM/MXene directional (PMD) hydrogel, its mechanical properties and conductivity are enhanced in a specific direction. At the same time, with the presence of the internal directional channels and the assistance of capillary force, the PMD hydrogel can achieve a volume deswelling of 70% in 2 s under light irradiation, further building a hydrogel actuator with a fast response performance. Additionally, the hydrogel actuator can lift an object 40 times its weight by a distance of 6 mm, realizing the advantages of both rapid responsiveness and high driving strength, which makes the hydrogel actuator have important application significance in remote control, microflow valve, and soft robot.     

3D-Printed Photoresponsive Liquid Crystal Elastomer Composites for Free-Form Actuation

Direct ink writing of liquid crystal elastomers (LCEs) offers a new opportunity to program geometries for a wide variety of shape transformation modes toward applications such as soft robotics. So far, most 3D-printed LCEs are thermally actuated. Herein, a 3D-printable photoresponsive gold nanorod (AuNR)/LCE composite ink is developed, allowing for photothermal actuation of the 3D-printed structures with AuNR as low as 0.1 wt.%. It is shown that the printed filament has a superior photothermal response with 27% actuation strain upon irradiation to near-infrared (NIR) light (808 nm) at 1.4 W cm⁻² (corresponding to 160 °C) under optimal printing conditions. The 3D-printed composite structures can be globally or locally actuated into different shapes by controlling the area exposed to the NIR laser. Taking advantage of the customized structures enabled by 3D printing and the ability to control locally exposed light, a light-responsive soft robot is demonstrated that can climb on a ratchet surface with a maximum speed of 0.284 mm s⁻¹ (on a flat surface) and 0.216 mm s⁻¹ (on a 30° titled surface), respectively, corresponding to 0.428 and 0.324 body length per min, respectively, with a large body mass (0.23 g) and thickness (1 mm).     

基于DSP与FPGA的四轴运动控制器设计与研究

针对数控系统的工作特点和要求,通过对DSPTMS320F2812、FPGAEP2C8F256C6及以太网控制器RTL8019AS的深入研究,设计了一种基于DSP与FPGA的运动控制器。该控制器以DSP和FPGA为核心器件,针对运动控制中的实时控制、高精度等具体问题,规划了DSP的功能扩展,并在FPGA上扩展了功能相互独立的四轴运动控制电路。该电路实现了四路控制信号输出,四路编码信号的接收和处理,以及原点信号,正负限位信号等数字量的接收和处理。具有结构简单、开放性、模块化等特点,能够较好的满足运动控制器的实时性和精确性。     

一种移动机器人的运动控制方法研究

针对反应式移动机器人运动控制中存在的缺乏自主运动规划等问题,介绍了一种新型移动机器人的运动控制方法。设计了一种混合式控制结构实现移动机器人的运动控制。采用基于行为的运动控制策略,将反应式行为和规划行为融合在一起。实验结果表明该策略能够很好地完成复杂环境下移动机器人的运动控制。     

Design and implementation of a cable-driven parallel robot for additive manufacturing applications

This paper presents a new 6 degree-of-freedom cable-driven parallel robot fully constrained by 8 cables. This robot should perform medium size 3D part printing. Its distinguishing feature is a radial cable winding that is relevant due to the small cable diameter (0.54 mm) and the maximum cable length (1.732 m, 1 m cube diagonal). This winding solution has the advantage of being compact and easy to design. The robot trajectory planning uses a full geometric model of the pulley and winding system which is introduced in this paper. The cable elasticity is taken into account in the geometric model to increase the tool path following accuracy. Robot dynamic performances are analyzed for two different mobile platform geometries. From this analysis, we obtained an end-effector trajectory tracking error of less than 0.4 mm for a feedrate speed of 0.1 m/s.     

A fast block-matching algorithm based on adaptive search area and its VLSI architecture for H.264/AVC

In this paper, we propose a fast block-matching algorithm based on search center prediction and search early termination, called center-prediction and early-termination based motion search algorithm (CPETS). The CPETS satisfies high performance and efficient VLSI implementation. It makes use of the spatial and temporal correlation in motion vector (MV) fields and feature of all-zero blocks to accelerate the searching process. This paper describes the CPETS with three levels. At the coarsest level, which happens when center prediction fails, the search area is defined to enclose all original search range. At the middle level, the search area is defined as a 7×7-pels square area around the predicted center. At the finest level, a 5×5-pels search area around the predicted center is adopted. At each level, 9-points uniformly allocated search pattern is adopted. The experiment results show that the CPETS is able to achieve a reduction of 95.67% encoding time in average compared with full-search scheme, with a negligible peak signal-noise ratio (PSNR) loss and bitrate increase. Also, the efficiency of CPETS outperforms some popular fast algorithms such as: three-step search, new three-step search, four-step search evidently. This paper also describes an efficient four-way pipelined VLSI architecture based on the CPETS for H.264/AVC coding. The proposed architecture divides current block and search area into four sub-regions, respectively, with 4:1 sub-sampling and processes them in parallel. Also, each sub-region is processed by a pipelined structure to ensure the search for nine candidate points is performed simultaneously. By adopting search early-termination strategy, the architecture can compute one MV for 16×16 block in 81 clock cycles in the best case and 901 clock cycles in the poorest case. The architecture has been designed and simulated with VHDL language. Simulation results show that the proposed architecture achieves a high performance for real-time motion estimation. Only 47.3 K gates and 1624×8 bits on-chip RAM are needed for a search range of (−15, +15) with three reference frames and four candidate block modes by using 36 processing elements.