# Design and Analysis of a Chinese Medicine Based Humanoid Robotic Arm Massage System
## 1 Introduction
This robot had the end of its arm in a series with three degrees of freedom, and a parallel wrist with three degrees of freedom served as the human hand which massaged. Additionally, two fingers were ineffective and the other fingers could undertake actions such as clicking, finger kneading, pinching, and rolling. Therefore, the five traditional kinds of actions which comprise Chinese medicinal massage techniques could be performed [19]. Furthermore, an increasing number of researchers are studying humanoid robot arms from the perspective of service robots [20; 21; 22; 23; 24; 25]. Therefore, Chinese traditional massage devices and massage robots can be adjusted passively by the masseur or the massage object, which makes it difficult to ensure the accuracy and reliability of the massage position. In recent years, much attention has been paid to massage equipment and massage robotic systems, which can be applied to many fields such as health care and rehabilitation therapy. The technical and functional characteristics of massage robot arms are as follows: (1) a relatively high degree of humanity and (2) an ability for remarkably complex movements and accurate grasp of massage force. In particular, a humanoid massage robot arm is rarely focused on configuration for realizing various massage techniques and precise recognition of a designated massage position. Furthermore, during the performance estimation of a humanoid Chinese medicinal massage robotic arm system, many factors including the weight of the arm and massage force size, direction, location, acupuncture point, and frequency should be taken into account. Therefore, a robotic arm with rigidity, high transmission accuracy, and anthropomorphic degree is highly desirable for the patients. To address the abovementioned shortage of medical personnel and improve the quality of life of the elderly and the disabled, a humanoid robot massage arm was designed on the basis of human arm massage theory. In this paper, a humanoid massage robot arm was mainly used in the field of traditional Chinese medicinal massage to realize massage of the lumbar spine and back. Accordingto the task function and control requirements, the humanoid massage robot arms were designed with the joint as the module based on the characteristics of a human skeleton and using massage theory according to traditional Chinese medicine, contrary to previous humanoid massage robot arms. The joints of the humanoid massage robot arm were connected together to realize the basic functions of a human-like arm by taking advantage of the working space and good flexibility of the serial robot. Binocular vision positioning technology was utilized to determine the precise massage position. Furthermore, a three-finger, dexterous massage hand and parallel robot massage were used to reproduce the techniques of experts. Moreover, the movement of the robot arm drove the dexterous hand and the parallel robot massage terminal to the designated position. In addition, the humanoid massage robot massaged the patient through the massage terminal at the front of the arm and the massage hand. Therefore, it was able to achieve the massage techniques (which can be considered as press, knead, pinch, roll, vibration) on the human lumbar spine and the back of the palm which stimulates meridian points and improves the ability of the immune system. Therefore, the natural posture of the arm of the humanoid Chinese medicinal massage robot is an important indicator of a massage robotic system [26]. Four degrees of freedom in a humanoid Chinese medicinal massage robotic arm (through serial structure in a series with the elbow, forearm, and wrist joints) can easily achieve this action with the arm. The mechanical structure of the humanoid massage robot arm was developed, investigated, and analyzed through a modular design concept, which was composed of a shoulder joint, elbow rotatory joint, wrist swing, and wrist rotatory joint.