The unique drive principle and strong manipulation ability of spider legs have led to several bionic robot designs. However, some parameters of bionic actuators still need to be improved, such as torque. Inspired by the hydraulic drive principle of spider legs, this paper describes the design of a bionic actuator characterized by the use of air pressure on each surface and its transmittance in the direction of movement, achieving a torque amplification effect. The produced torque is as high as 4.78 N m. In addition, its torque characteristics during folding motions are similar to those during unfolding motions, showing that the bionic actuator has stable bidirectional drive capability.

The study researched the orifice flow equation when the flow state of the orifice is laminar. Based on the novel flow equation and the expected linear flow equation, a compensator is designed to compensate the non-linearity and make the flow characteristics linear. The characteris-tics experiment result shows that the flow after compensa-tion control is close to the expected flow, in which the pres-sure difference was increased from 0.5MPa to 4MPa, and the error is less than 20%. When the compensator is used as feed forward control in the EHSS and compound with proportional (P) control, the sinusoidal response error with frequency of 0.5Hz and amplitude of 5mm is within 0.4mm under large external load. While the error of the uncompensated system is up to 0.8mm. The compensator can be used into the electro-hydraulic system with larger load disturbance and improve the control performance compounded with the simplest proportional (P) controller.

In order to improve the performance of the negative overlapped valve controlled asymmetrical cylinder system, a theoretical zero point model of the valve with symmetric and unequal negative overlap was established. The simulation results showed that the zero point of the system will shift as the load changes, and the error of the theoretical zero point is relatively larger in some certain pressure states. In order to find the zero point quickly and steadily and improve the positioning accuracy of the system, a zero point compensation controller based on theoretical zero point plus error integral control was designed. Compared the pure P controller with the compound control of P controller and zero point compensation controller, the control accuracy of the system has been greatly improved under transient load and sinusoidal load interference.