The mechanical and electronics design of a quadrupedal walking robot featuring 12 pneumatically actuated degrees of freedom is presented. Control of the robot's joint motions incorporates open-loop damping into the actuation and uses a stance/swing gain scheduler in the joint position controller. The inclusion of these two attributes enables stable and robust joint-level control while attenuating the undesirable oscillatory modes that are commonly associated with pneumatically actuated walking robots. Joint motion trajectories that permit stable walking are developed and implemented in the robot. The combination of these features and techniques is experimentally shown to enable stable walking locomotion of the robot that is not inhibited by unwanted oscillations of significant magnitude.

The authors have designed and constructed a new type of actuation for a spherical robot. The proposed actuation system consists of a large number of individually inflatable rubber bladders covering a sphere. Inflation of one or more of these bladders imparts a moment to the sphere and coordinated inflation results in a directed motion. Further, the authors introduce a scheme for steering the robot by correctly selecting the proper bladders to inflate so that motive force is developed in a specified direction. The control scheme utilizes a passively rolling inner vehicle with a directional, remotely positioned light source that causes valves housed within the sphere to inflate the designated bladders through optical commutation.

This paper presents the design of a gas-actuated anthropomorphic arm prosthesis with 21 degrees of freedom and nine independent actuators. The prosthesis utilizes the monopropellant hydrogen peroxide as a gas generator to power nine pneumatic type actuators. Of the nine independent actuators, one provides direct- drive actuation of the elbow, three provide direct-drive actuation for the wrist, and the remaining five actuate an underactuated 17 degree of freedom hand. This paper describes the design of the prosthesis, including the design of small-scale high-performance servovalves, which enable the implementation of the monopropellant concept in a transhumeral prosthesis. Experimental results are given characterizing both the servovalve performance and the force and/or motion control of various joints under closed-loop control.

This paper presents the design of an anthropomorphic 21 degree-of-freedom, 9 degree-of-actuation arm prosthesis for use by transhumeral amputees. The design leverages the power density of pneumatic actuation with the energy density of liquid propellants to obtain a self-powered dexterous prosthesis in which all of the requisite power, actuation, and sensing is packaged within the volumetric envelope of a normal human arm. Specifically, the arm utilizes a monopropellant as a gas generator to power nine pneumatic-type actuators that drive an elbow, three wrist degrees-of-freedom, and a 17 degree-of-freedom compliant hand. The design considerations discussed in this work include the design of compact, low-power servovalves; the choice of actuators based on energetic requirements of a normal arm; the design of compact elbow and wrist joints with integrated position and force sensing; and the components of the compliant hand design. The liquid-fueled prosthesis is expected to approach the dexterity of an anatomical arm and is projected to deliver half of the force and power output of an average human arm.

This paper presents a method for the control of locomotion in a robot hexapod. The approach is based on the WalkNet structure, which in turn is based on the neural control structure of the insect Carausius morosus. Though the WalkNet structure has been shown to function well in kinematic (i.e., non-dynamic) simulations, the authors found that the approach to coordinated control of hexapedal locomotion entailed several significant problems when simulated in the presence of dynamic effects, including gravitational effects, inertial dynamics, and ground contact dynamics. As such, the authors propose several variations on the WalkNet structure that provides stable and robust locomotion in the presence of dynamics, while still maintaining the attributes of WalkNet coordinated control, including self-selection of gait and associated emergent behaviors. The approach is simulated in the presence of dynamics and shown to provide stable gait with emergent characteristics.