气动柔性果蔬采摘机械手运动学分析与实验

采用气动弯曲型柔性驱动器设计了一种带有柔性机械臂的多自由度果蔬采摘机械手。基于分段常曲率理论,根据柔性驱动器形变规律,建立了多关节串并联的采摘机械手运动学模型和抓持力模型,研究了机械手采摘作业时抓取模式、工作空间和手指输出力与气压的关系,并进行了相关实验验证。制作了机械手样机,并在实验室环境下进行了多种果蔬模拟采摘实验,结果表明,该果蔬机械手具有多种抓取模式,且动作灵活、柔顺可靠、易于控制,适用于球形和圆柱形果蔬自动化采摘作业。

Kinematics Analysis and Experiment on Pneumatic Flexible Fruit and Vegetable Picking Manipulator

A multi degree of freedom fruit and vegetable picking manipulator with a flexible arm was developed according to the bending flexible pneumatic actuators which had large bending capabilities. The static characteristic and deformation of the bending actuators were studied, and then the kinematics model of picking manipulator was established with multiple tandem joints by using homogeneous coordinate transformation and piece wise constant curvature model. At the same time, the grasp force of the picking manipulator when grasp the different objects was analyzed. In order to adapt to different grasp objectives, the grab modes were set when the robot picked the objects, and then the relationship between finger output force and air pressure was studied. Also, the picking manipulator movement track and work space were got by markers position change with air pressure. Through the simulation of the manipulator by Matlab software, it can be seen that the picking robot can complete five finger grasping, four finger grasping and two finger grasping gestures by cooperation of flexible fingers. Subsequently, the relevant experiments were carried out to verify the theoretical model. A prototype of the picking manipulator was made and a variety of fruit and vegetable simulation picking experiments were carried out in the experimental environment. The results of harvesting experiments showed that the picking manipulator had flexible movements and high adaptability to the shape of object. It had multiple grasping modes and was easy to control, which can grasp objects of different shapes and weights stably, especially suitable for automatic picking of spherical and cylindrical fruits and vegetables.