Papers by Author: Yu Lei Hou

Abstract: This paper presents a novel parallel tri-axis force sensor with decoupled feature, and performs its performance analysis. Firstly, the structural characteristics of the parallel tri-axis force sensor are introduced and the stress distribution of each limb elastomer is analyzed. To measure the transformation relationship between the force and strain, the electric bridge is formed by pasting strain on the elastic-sensitive element. Then, the finite element simulation of the elastomer is conducted and performance analysis of the sensor is carried out, which shows that the parallel tri-axis force sensor is decoupled, linear and fully-isotropy. The sensor possesses good static performance and can meet the requirements of tri-axis force measurement in general industrial production. The contents of this paper riches the structure type of the multi-component force sensor and will be useful for the research and development of the parallel force sensor.

Abstract: The existence of coupling makes the parallel mechanism possess some special advantages over the serial mechanism, while it is just the coupling that brings about the parallel mechanism some difficulties in kinematics and dynamic analysis, the development of control system, and the trajectory planning. Therefore the research on the decoupled parallel mechanism becomes one of the hot of the mechanism fields. While whether the parallel mechanism can realize decouple is the premise for synthesis and analysis of the parallel mechanism. Based on screw theory, the existence of the three degrees of freedom (3-DoF) rotational fully-decoupled parallel mechanism is distinguished. Then taking the 6-PUS/UPU parallel mechanism as example, the rotation angles of the moving platform are measured, which is verified the impossibility of the 3-DoF rotation decoupling. The contents of this paper should possess theoretical significance for the innovative configuration synthesis and structure design of rotational decoupled parallel mechanism.

Abstract: In the field of spatial orientation, the rotational parallel mechanism is widely used. While the existence of coupling brings about the parallel mechanism some difficulties in kinematics and dynamic analysis, the development of control system, and so on. This condition restricts the application fields and effects of the rotational parallel mechanism. Therefore, this paper proposes a novel 2-DOF (two degrees of freedom) rotational DPM (decoupled parallel mechanism). The feature of the mechanism is described and their movement form is analyzed with screw theory. The proposition of the novel rotational DPM will enrich the configurations of the parallel mechanism, and the contents of this paper should be useful for the further research and application of the rotational parallel mechanism.

Abstract: For the real-time pose adjustment of the sub-reflector of antenna to ensure its best condition, Stewart platform-based mechanism is adopted. This paper presents the configuration optimization of the adjusting parallel mechanism taking the minimum force acted on each limb as the target, and the basic structural parameters of the mechanism are obtained. Considering the weight of the moving platform, the external load, and the influence of the snow and the wind, the maximum force acted on the limbs of the mechanism in the required workspace is calculated, which established the foundation for the structural design of the mechanism. The contents of this paper possess theoretical significance and engineering value for the development of the adjusting mechanism for the sub-reflector of antenna.

Abstract: Six-axis force sensors based on Stewart platform necessitate highly accurate, sensitivity and dynamic response. In response to this need, errors analysis and compensation of the force sensor are essential. In this paper, the measurement error generated by the upper platform deformation is discussed and evaluated. Furthermore, in order to improve the precision, a real-time compensation algorithm is proposed depending on the external force applied on the force sensor. Finally, a numerical simulation example is presented, which indicates that the precision is related to the stiffness of limbs directly and improved obviously by the compensation algorithm.

Abstract: Based on the bionics principle, this paper proposed the idea of bionic design of the spherical parallel shoulder joint integrated with the six-component force sensor. The static analysis of the 3-RRS mechanism, which can be taken as a prototype mechanism of shoulder joint of humanoid robot, was carried out. And the relationship figures between the forces and torques acted on each component and the pose of the mechanism were obtained. The measurement of the external load and driving torques, which was employed to judge operability of arm to the target object under arbitrary pose, was realized by introducing resistance measurement method in the mechanism. The bionic integration of the shoulder joint with six-component force sensor made arm has some functions such as to avoid overload and singular area voluntarily, and realize self-protection. The contents of this paper lay a foundation of compliant control of humanoid robot arm and have important significance and value in engineering.