Human-in-the-Loop Gait Stabitlity Analysis And Control Strategy Of Biped Walking-Chair Robot

The researches on the robot for the disabled have developed rapidly, and a large number of achievements have been made. Biped human-carrying robot is one important part developed based on the traditional biped robots for the older or the disabled to walk as a normal person. It gives a new alternative for the disabled to replace a wheelchair or artifical leg. It has stronger adaptation to complex environmental than wheelchair. It can walk on the sloping surface or up and down the stairs. The human-carrying robot is required to walk more stable than the traditional biped robots for ensuring the human safety, furthermore, the large load and the interference of the human motion in the loop cause the stability control more difficult. The effective information of human body must be detected and its influence to the gait stability must be analysed to ensure the robot walk safely. So the in-depth research on the gait stability control with human in the loop is necessary to guarantee the biped human carrying system absolute safety.The biped walking-chair robot JWCR with 12 freedoms is introduced as the platform for our experiments. Its characteristic is analysed and its gait stability control is studied by simulation referring to existing research achievements. The conception of human-in-the-loop system is introduced, which means the human control the device to achieve the target according to the environment's information, at the same time, the human's influence to the system is considered. The main researches include:1. The main characteristics of the biped human-carrying robot JWCR are intruduced. The orthotropic joints are used for the robot to compact the configuration and simple the calculation. A foolproof apparatus is designed for the knee joint to reduce motor rating power with a large load. A passive hanging device is designed to reduce the shake caused by the passenger's relative movement. Passive and active passenger safety protection devices are designed to keep passenger safe.2. Considering the human carrying robot to be a system with human in the loop, the eight-pole model for the forward movement and the six-pole model for the sideways movement are established and analysed. The kinematics and reverse kinematics model is built up for the forward movement. The robot's kinetic model is set up with Lagrange Equation based on the above model. 3. The Zero Moment Point (ZMP) criterion is used for the robot's off-line gait plan and stability analysis, including the starting gait, walking gait and stop gait. The simulation experiments by Matlab are used to verify the feasibility of the planned gait.4. In order to realize the robot's real-time control, the influence of the passenger's fluctuation parameters as interference source to the gait stability is analyzed. The fluctuation of the passenger's physical parameters includes body height, weight and motion parameters.5. The real-time control system with human in the loop is built up. The stability control method combined of local adjustment and passenger's compensation motion is introduced to keep the gait smooth and reduce the fluctuation of the system. The strategy of compensation for the human motion is given. The simulation experiments by Matlab and Adams are used to verify the feasibility of the strategy.This dissertation is supported by the National Natural Science Foundation of China project named'research on the biped human-carrying robot's gait stability control'(60575049).