2803 Lei Jingtao （雷静桃）*, Zhu Jianmin**, Wu Jiandong*
Trajectory tracking control of the bionic joint of the musculoskeletal leg mechanism
Abstract Pneumatic artificial muscles (PAMs) have properties similar to biological muscles, which are widely used in robotics as actuators. It is difficult to achieve highprecision position control for robotics system driven by PAMs. A 3DOF musculoskeletal bionic leg mechanism is presented, which is driven by PAMs for quadruped robots. PAM is used to simulate the compliance of biological muscle. The kinematics of the leg swing is derived, and the foot desired trajectory is planned as the sinusoidal functions. The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints. A proportional integral derivative (PID) algorithm is presented for controlling the flexion/extension of the joint. The trajectory tracking results of joints and the PAM gas pressure are obtained. Experimental results show that the developed leg mechanism exhibits good biological properties.
Key words: musculoskeletal leg mechanism, swing, bionic joint, trajectory tracking, proportional integral derivative (PID) control
Robust adaptive beamforming for constant modulus signal of interest
Abstract It is required in the diagonally loaded robust adaptive beamforming the automatic determination of the loading level which is practically a challenging problem. A constant modulus restoral method is herein presented to choose the diagonal loading level adaptively for the extraction of a desired signal with constant modulus (a common feature of the phase modulation signals). By introducing the temporal smoothing technique, the proposed constant modulus restoral diagonally loaded robust adaptive beamformer provides increased capability compared with some existing robust adaptive beamformers in rejecting interferences and noise while protecting the signalofinterest. Simulation results are included to illustrate the performance of the proposed beamformer.
2801 Liu Yuzhe (刘宇哲)* **, Wu Jun* **, Wang Liping***, Zhao Jingshan*, Wang Jinsong* **, Yu Guang* **
A novel symmetrical 3DOF PKM and its performance comparison with 3PRS PKM
Abstract A novel symmetrical 3degreeoffreedom (DOF) parallel kinematic manipulator (PKM) is firstly presented, which is named 3P (Qu) RU. According to the structure feature, a double closed loop vector method is proposed to investigate this PKM.Based on this method, kinematic, velocity and error models of this manipulator are established respectively. Since3PRS PKM has been applied successfully in practice and its structure is similar to the 3P (Qu) RU PKM, corresponding models of a 3PRS PKM are given and a performance comparison study between them is investigated on workspace, manipulator dexterity, position error and error sensitivity. The comparison results reveal that the 3P (Qu) RU PKM has the advantage on velocity performance and the disadvantage on accuracy performance. This novel 3P (Qu) RU PKM is an available selection for a tool head of a hybrid machine tool and the analysis is greatly helpful for the further applications of this manipulator.