A robotic grinding system requires a force-controlled grinding module to provide a consistent surface roughness and a robot arm to position the grinding module to reach a wide range of surface area on a workpiece. Existing pneumatic grinding modules are heavy and bulky and cannot provide very accurate force control. Articulated 6-axis robot arms are often used for positioning the grinding module, but they require a large accommodation space and have limited access to the surface of a spherical workpiece. This paper proposes a compact 3-axis grinding robot with no grinding surface limitations on spherical workpieces. The robot employs torque-controlled actuators so that a human operator can easily teach grinding paths to the robot. The proposed grinding module uses series elasticity to generate very low reflected inertia and friction. Hence, accurate grinding force control can be achieved. The grinding module also has a small size and low noise. Experimental results verify the high accuracy of grinding force control when compared with existing counterparts. Through an illustration of removing the parting line of a helmet hardshell, the grinding robot can effectively reduce the surface roughness of workpieces that are sensitive to the grinding force. It is expected that the proposed robot can be easily reconfigured to grind workpieces of different geometries.

中文翻译：

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一种紧凑型柔顺机器人，用于磨削球形工件，具有高力控制精度


机器人磨削系统需要力控制磨削模块来提供一致的表面粗糙度，并需要机器人臂来定位磨削模块以到达工件上的大范围表面区域。现有的气动研磨模块笨重且体积大，并且不能提供非常精确的力控制。铰接式六轴机械臂通常用于定位磨削模块，但它们需要较大的容纳空间，并且接触球形工件表面的能力有限。本文提出了一种紧凑型三轴磨削机器人，对球形工件没有磨削表面限制。该机器人采用扭矩控制执行器，以便操作员可以轻松地向机器人教授磨削路径。所提出的磨削模块利用串联弹性来产生非常低的反射惯性和摩擦力。因此，可以实现精确的磨削力控制。研磨模块还具有体积小、噪音低的特点。实验结果验证了与现有同类产品相比磨削力控制的高精度。通过去除头盔硬壳分型线为例，磨削机器人可以有效降低对磨削力敏感的工件的表面粗糙度。预计所提出的机器人可以轻松地重新配置以磨削不同几何形状的工件。