Objective-based Iterative Learning Control for Robotics and Rehabilitation

该项目的目的是开发并显著增强一项令人兴奋的新技术，该技术已被证明可以帮助中风患者恢复手臂功能。这项技术是基于使用电刺激来帮助受试者进行他们无法控制的手臂运动。通过使肌肉活动，电刺激解决了人们中风后试图重新学习技能的问题。问题是，重新学习技能需要练习，这需要反馈，而当你的手臂完全无法移动时，你就无法获得反馈。人们在中风后重新学习技能的过程与你学习打网球的过程完全相同。你会变得更好，因为在你的大脑和脊髓中建立了新的神经连接。你不仅需要练习，你还需要你的表现反馈，这样你就可以纠正你的动作。当对肌肉施加电刺激时，电脉冲沿着神经传播的方式与来自大脑的电脉冲非常相似。如果仔细控制刺激，可以做出有用的动作。如果这个人自己尝试这个动作，那么重新学习的过程会更好。最近的创新研究利用了这一事实，将人自己的努力与足够的电刺激相结合，以实现预期的运动。在这项研究中，研究对象通过对肱三头肌进行电刺激来进行水平伸展运动。他们的任务是跟踪在他们面前缓慢移动的光点，并使用一种称为“迭代学习”的技术来决定使用什么刺激来帮助他们准确地完成跟踪任务。通过仔细地改变这种刺激，以最好地帮助受试者，这项研究已经确定，电刺激能够帮助人们在中风后重新学习运动。该项目的目的是在治疗期间最大限度地提高电刺激的治疗效果。还将为开发一种可在患者自己家中使用的廉价系统奠定必要的基础，以增加获得这种创新技术的机会。而实现这一目标的方法便是将“迭代学习”发展成一种更强大且更灵活的控制刺激的工具。然后，它将被用来帮助人们完成更自然的动作，比如拿起瓶子倒酒，按一系列按钮，转动把手。由于这些任务对日常生活很重要，这项技术可以直接帮助患者重新学习对他们最有用的任务。另一个优点是，“迭代学习”也将能够响应监督治疗的物理治疗师的愿望。如果他们认为受试者试图做的动作不理想，他们将有自由改变刺激帮助受试者完成动作的方式。此外，将任务呈现给人们的简单方式意味着只需要很少的设备，因为不需要显示轨迹，不需要对运动进行任何形式的约束，也不需要使用任何机器人辅助。因此，这消除了阻碍这项技术从实验室进入患者家庭的一个实质性障碍。虽然该技术的应用重点是中风康复，但“迭代学习”所带来的灵活性也将使许多工业过程受益。这些例子包括在生产线上一遍又一遍地执行相同操作的机器人。这种灵活性将为重复任务的执行提供自由变化的方式，以最大限度地提高效率，响应任务的变化，并满足所需的约束。这一切都将实现，同时仍然保持高度的准确性。

The purpose of this project is to develop and significantly enhance an exciting new technology that has been shown to help stroke patients regain arm function. This technology is based on using Electrical Stimulation to assist subjects in performing arm movements which they cannot otherwise manage. By making muscles work, Electrical Stimulation solves the problem that people have when they try to re-learn skills after having a stroke. This problem is that re-learning skills takes practice, and this requires feedback which you can't get when you are unable to move your arm at all. The way in which people re-learn skills after a stroke is exactly the same process as you do when you learn to play tennis. You become better at it, because new nerve connections have been made within your brain and spinal cord. Not only do you need to practice, but you also need feedback of your performance so that you can correct your movement.When Electrical Stimulation is applied to muscles, electrical impulses travel along the nerves in much the same way as the electrical impulses from your brain. If stimulation is carefully controlled, a useful movement can be made. The re-learning process works better if the person is attempting the movement themselves. Recent innovative research has exploited this fact by combining a person's own effort with just enough Electrical Stimulation to achieve the intended movement. This research involved subjects performing horizontal reaching movements with Electrical Stimulation applied to their triceps. Their task was to track a spot of light as it moved slowly in front of them, and a technique called 'Iterative Learning' was used to decide what stimulation to apply to help them perform the tracking task accurately. By carefully varying this stimulation to best assist the subject, this research has established that Electrical Stimulation is able to help people re-learn movement after a stroke.The aim of this project is to maximise the therapeutic benefit of Electrical Stimulation during treatment. Foundations will also be laid that are necessary for the development of an inexpensive system that can be used in patient's own homes to increase access to this innovative technology. The way in which this will be done is to develop 'Iterative Learning' into a much more powerful and flexible tool for governing the stimulation. It will then be used to help people perform far more natural movements such as picking up a bottle and pouring from it, pressing a series of buttons, and turning a handle. Since these sort of tasks are important for day to day living, the technology then directly helps patients re-learn the tasks that are most useful to them. Another advantage is that the 'Iterative Learning' will also be able to respond to the wishes of the physiotherapist who supervises the treatment. If they decide that the movement the subject is trying to do is not ideal, they will have the freedom to change the way in which the stimulation helps the subject perform the movement. Furthermore, the simple way in which the tasks are presented to people means that very little equipment is needed, as there is no trajectory to display, no form of constraint to the movement, nor any robotic assistance used. This therefore removes a substantial obstacle preventing the technology from moving from the lab and into patient's homes.Although stroke rehabilitation is the application focussed on, the added flexibility given to 'Iterative Learning' will also benefit many processes that are found in industry. Examples of these include robots which perform the same operation over and over again in production lines. This flexibility will give the way in which the repeated task is performed the freedom to vary in order to maximise efficiency, respond to changes in the task, and satisfy desired constraints. This will all be achieved whilst still maintaining a high degree of accuracy.