The Bionic Control Research Of Robot Knee Joint

Research and development of biped robot has become a hot topic in the field of robotics, the knee joint in the process of biped robot movement not only serve as the role of driving force, but also can ensure the movement in the process of coordination and stability of the robot body.Therefore, choosing the right drive and control strategy for robot control effect of the knee joint has very important significance, thus make the robot more anthropomorphiced.The project include the joint mechanical structure design, the choice of drive mode, control algorithm of research.For knee joint mechanical structure design, combining the characteristics of the human knee joint in the biomedical, adopts the mechanical structure of the four connecting rod, not only imitated natural disposition is strong, but also improved the stability of the mechanical structure; For a robot knee drive mode, driven by pneumatic artificial muscle as a way, should avoid rigidity large motor drive, hydraulic drive, pneumatic artificial muscle in design was more anthropomorphiced, fully imitate the human body the working characteristics of the leg muscles; For mathematical modeling of pneumatic artificial muscle, this article subverts the traditional modeling methods, through constructing the performance of the pneumatic artificial muscle testing experiment platform, respectively study under different conditions, the output power, input pressure and the complicated relation between shrinkage rate, directly from the experimental data, this paper establish meet certain artificial muscle characteristics, the mathematical model can be applied to a better process control; For the construction of the joint control simulation platform, adopt the classic control simulation system of virtual prototype, using PRO E draw assembly drawings of the robot, by ADAMS to verify the improvement of the mechanical system, the control through the Simulink simulation; Physical systems and control platform, using the industrial PC and motion control card control motor and pneumatic artificial muscle respectively, respectively by the encoder and 6 force sensor will turn each joint Angle and force feedback back to the industrial computer.Subject respectively adopts PID control algorithm and the equivalent sliding mode control algorithm to control simulation robot knee joint.The simulation results show that the equivalent sliding mode control algorithm is better than PID controller, and can make the robotknee better to follow the target trajectory, the tracking error is small, robust.visible, to control a robot with a nonlinear systems or pneumatic artificial muscle, using sliding mode control algorithm is an effective method.