To sort different sizes of apples, a kind of passive grab cable-driven of flexible manipulator is designed. Each finger consists two single degree-of-freedom joints and a torsional spring is installed on each joint. The two-point of finger is stretched by a cable, which is connected to pistonstem of cy- linder. However, when the cable looses,the torsional spring drive the finger bend and grab the apple. The objective function is determined by the minimum change range of grasping force, Which can be optimized by the fmincon-function provided by the software MATLAB. We can conclude that: twist the stiffness of hydropneumatic spring arek2 andk3 ,preloaded angle areΦ02 andΦ03, moreover it show that the manipulator has a good supple adaptation without causing damage to apple.

The practice shows that complex lapping motion trajectory can decrease the adverse effects caused by the lapping direction which has a great influence on the lapping of the natural single crystalline diamond cutting tool. For example, addition of a reciprocating motion can get better lapping performance and surface roughness. On some kinds of natural diamond cutting tool lapping machines a further improvement is made by designing an additional planetary spindle to provide planetary motion to the main shaft, which offers a more complex motion trajectory. With an increase in degrees of freedom of the lapping machine, it becomes difficult for technicians to master a good suit of motion process parameters. This paper proposes a set of methods to plan the lapping trajectory with respect to the machine that can perform complex lapping motion. Firstly, the proposed method designed a statistical parameter which is the variance of the direction angle distribution for the lapping velocity and its calculation method to evaluate the complexity of the trajectory. And then the multi-body kinematics model was established by using Simulink tool box in Matlab software for the purpose of model kinematics simulation and outputting data for calculation of the statistical parameter above. Finally, the genetic algorithm was used to find the best motion parameters of every shaft under certain restrictions. The advantage of the set of lapping trajectory planning method presented in this paper is that it combines the powerful multi-body simulation and signal processing ability of Simulink tool box and the characteristics of the genetic algorithm in almost no limitation on awaiting optimization function and suitable for complicated problems. So the method provides not only a way for planning complex diamond lapping trajectory but also a general approach to solve the problem on machine motion process parameters optimization.

Molecular dynamics is a rapidly developing field of science and has become an established tool for studying the dynamic behavior of material machining. A three-dimensional molecular dynamics (MD) model about the atoms of the diamond cutting tools and the diamond grits is built by using the molecular dynamics. The Tersoff potential function is used to calculate the force and potential energy among the atoms of the diamond tools and the atoms of the diamond grits. The lapping processes at a special cutting depth are simulated. The variety of the specimen potential energy in the lapping process is observed. The mechanism of the diamond micro machining and the form of the surface formation are given by comparing the distribution maps of atoms in initial and cutting states. This study will give a strong support to the diamond cutting tools’ lapping.

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In the respect of ultra-precision manufacturing of axisymmetric surface, the machine tool with tool swing feeding has less interpolation error sources compared to the conventional ultra-precision diamond turning machine tool. The installation errors of machine tool greatly affect the manufacturing accuracy of parts. Therefore, based on the multi-body dynamics theory , the structure characteristics of this machine tool, and the parts' relative positions of machine tool, in this paper we established the space geometric model and the integrated error model of machine tool integrated with the actual installation error of machine. The analysis results of the error model show that the relationship between the depth of axis (tool shaft and main shaft of machine) parallelism and the profile error is linear function; when the installation error of swing arm was lower than 150′′,the profile error of parts was less than λ/10.