## 5 Experiments on a Prototype of a Lower Limb Exoskeleton Rehabilitation Robot  
### Hardware System Design of Lover Limb Exoskeleton Rehabilitation Robot  
Biomechanical analysis of human gait rehabilitation and exoskeleton structural design revealed distinct joint energy characteristics: quantitative measurements showed the hip and knee exhibited the highest energy dissipation, whereas the ankle demonstrated minimal energy dissipation along with greater passive mobility and lower control complexity. Consequently, our actuation strategy prioritizes active control of hip and knee flexion/extension using brushless DC motors, while maintaining passive compliance in other degrees of freedom through optimized spring-damper mechanisms.  
1. Hip and knee drive systems  
When the human body walks normally, the maximum power is about 100 W, and the maximum torque of the hip joint during walking is about 115 Nm (including the standing support phase). Considering the problem of control margin, and with reference to the characteristics of the exoskeleton rehabilitation robot for lower limbs, a thin and lightweight disc motor with a small volume is selected as the actuator of the hip joint system. The MYACTUATOR LSG-32-142-80 model (rated torque 153 Nm) is selected for the drive system of the hip joint.  
When the human body walks normally, the maximum power is about 60 W, and the maximum torque of the knee joint during walking is about 41 Nm (including the stage of standing support), so the MYACTUATOR LSG-25-110-50 model (rated torque of 82 Nm) is selected for the knee joint drive system.  
2. Pressure sensor system  
The purpose of choosing pressure sensors in this paper is as follows: according to the change of plantar pressure to analyze the interplay of forces and moments on the joints of the lower limbs, and then discern the patient's active/passive gait rehabilitation cycle training effect during the gait rehabilitation training [20]. The mounting locations of the pressure sensors are as follows: at the forefoot of the right and left feet, at the middle part, and at the heel. The pressure sensors required in this paper need to be as small as possible, so the L-10M-100 KG type sensor was used.  
The exoskeleton rehabilitation robot for the lower limbs designed in this paper uses an upper computer to control the robot to perform passive rehabilitation training on the affected limbs, and adopts a multi-joint linkage gait rehabilitation training method. The overall hardware system of the lower limb exoskeleton rehabilitation robot system is shown in Figure 12. The lower unit of the control circuit is centered on the motion control card and the data acquisition card, and the motion control card completes the motion control of the  
Figure 11: Control input curves for each joint of a lower limb exoskeleton rehabilitation robot. (**a**) Hip joint control input curve; (**b**) knee joint control input curve.  
lower limb hip and knee flexion/extension; the information acquisition card completes the data acquisition of each sensor. The upper computer helps the patient carry out appropriate rehabilitation training by setting the parameters of each joint movement, and then transmits the relevant parameters to the motion control card; the data collected by all sensors are transmitted to the data acquisition card.