EMG control of a pneumatic 5-fingered hand using a Petri net

This article presents the control method for a 5-fingered artificial hand using electromyography (EMG) signals. Our targeted artificial hand is driven by pneumatic actuators to reduce its weight, and we use ON/OFF solenoid valves instead of electro pneumatic regulators to simplify the control system. The pneumatic hand has 15 degrees of freedom, and it seems difficult to reproduce all the finger motions from the EMG signals only. Therefore, we describe typical hand motions using a Petri net, and control the finger motions efficiently based on this model. Each state of the Petri net indicates one step in the hand posture to complete the intended motion. Simultaneously, this state corresponds to the ON/OFF pattern of the 15 solenoid valves. This enables the operator to control the 5-fingered dexterous hand smoothly, transiting the state in the Petri net according to the EMG motion signals. We conducted an experiment to verify the validity of the proposed method. In the experiment, five typical motions (spherical grasp, power grip, hook grip, key grip, precision grip) were successfully performed using the 6-channel EMG signals measured from the operator’s forearm.