On October 26th, at the 3rd Global Assistive Technology "Olympics" (also known as the "Half Robot Bionic Olympics") held in Zurich, Switzerland, Chinese athlete Xu Min ultimately won the championship in the "Upper Limb" category with a score of 90 points, using the missing right forearm embedded in a prosthetic limb to quickly complete tasks such as lifting heavy objects, grabbing paper, stacking cups, winding iron rings, and retrieving items from blind boxes without any mistakes. The scientific research team of Southeast University and Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences "fought side by side" with Xu Min. They enhanced the reliability, load-bearing capacity, and dexterity of the prosthetic limbs, allowing Xu Min to beat her opponents and win the championship. This championship is also the best result achieved by Chinese athletes in the world's top technology assisted disability events. The Global Assistive Technology "Olympics" was founded by the Swiss Federal Institute of Technology Zurich and is held every four years. In this competition, the upper limb prosthetic group is one of the most fiercely competitive groups. Contestants are required to complete 10 prosthetic operation tasks at once, including lifting heavy objects with prosthetic limbs, dual arm cooperation, fine object grasping, and blind box grasping. The score will be determined by the number of tasks completed and the completion time. The upper limb prosthetic team representing China is composed of 7 people, including 5 researchers from Professor Song Aiguo's team at the Institute of Robot Sensing and Control Technology, Southeast University, in addition to contestant Xu Min. The prosthetic limbs used in this competition have three core technologies, namely decoding and recognition of electromyographic signals, force perception and feedback, and design of dexterous mechanisms Introduction to Song Aiguo. So, how do prosthetics work with the human body to complete as many movements as possible in the shortest possible time? Before making a certain action, a person's brain first perceives the surrounding environment and then generates brainwaves. Brain waves are transmitted along the spinal cord nerves, and when they reach the forearm, electromyographic signals control muscle contractions, which in turn drive movement. To enable disabled people to flexibly use prosthetic limbs, it is necessary to help them decode and recognize electromyography Song Aiguo explained that the research and development team applied a pair of electrode pads on the skin of the athlete's forearm limb, which were used to interpret and recognize the residual limb electromyographic signals, and then connected them to the prosthetic limb to drive its movement. In the competition, disabled athletes will manipulate prosthetic hands to grasp various objects, but due to the limited signal sources for disabled people to control prosthetic limbs, ensuring reliable movement of fingers and wrists has become a problem that needs to be overcome. Hu Xuhui, the team leader and postdoctoral fellow of the Chinese Academy of Sciences Suzhou Institute of Biomedical Engineering Technology, said: "We customized Xu Min's wearable shoulder belt. There is a tension sensor in the shoulder belt, which can monitor Xu Min's shoulder movement state when he backs his bow. The sensor controls the opening and closing angle of the fingers and the rotation angle of the wrist joint by monitoring the shoulder displacement signal and cooperating with the EMG signal obtained from the stump end. The larger the bow back angle is, the greater the shoulder displacement is, and the greater the opening and closing degree of the fingers is. And vice versa." In the competition, the players have to grasp objects and complete actions that vary greatly, sometimes they can carefully twist the bulb, reverse the wrist and stack cups, and sometimes Be able to lift mineral water bottles, hold hammers and carry kettles. How to control the force on the 'hands'? Song Aiguo introduced: "The team has implanted force tactile sensors on the fingers of the prosthetic limb to detect the magnitude and distribution of the prosthetic limb's grasping force when grasping objects. The signal can be transmitted to the arm through vibration stimulation. If the grasping force is greater, the vibration stimulation will be stronger, and the hand can decide how much force to apply based on the vibration intensity." Although the movements in the competition are all from daily life, grasping some fine movements or special objects still poses challenges for people with upper limb disabilities. In response, the team designed prosthetics tailored to local conditions to make them more flexible and stable. For example, we have set up four different grasping areas on the prosthetic finger. The first functional area should be made as horizontal as possible to grip flat objects such as paper and medicine spoons. The second functional area should be made into an embedded circular arc shape to grip objects such as hammers and bottles. The third functional area should be made into a hemisphere to grip circular objects such as beads. The fourth functional area should be set at the two joints of the fingers to facilitate fixing the position of objects during weight-bearing actions such as lifting water bottles Hu Xuhui said. To complete the prescribed movements with as few mistakes as possible in the shortest possible time not only tests the stability and accuracy of prosthetic development technology, but also requires strong perception of complex competition environments. Hu Xuhui introduced that there is a competition similar to "blind box opening", which requires the prosthetic limb to pass through a covered brush and grab cylinders of different hardness without being visible to the naked eye. In order to give the prosthetic limb "eyes", the team installed cameras in the prosthetic limb fingers and used visual recognition technology to convert the captured image signals into light signals, assisting Xu Min in grasping and making her the only contestant among all participating teams to complete this task. This championship has made us realize that scientific research should be based on meeting the needs of people with disabilities. In the future, we will develop prosthetic hands with stronger human-machine integration, more practical operation functions, and lighter daily use, benefiting the disabled population Hu Xuhui stated. (New Society)