Haptic feedback for virtual reality

A virtual reality system configured to provide haptic feedback to a user, comprising:

• a controller;
• determination means for producing output data representative of an orientation and/or velocity and/or acceleration of an upper arm of the user and an orientation and/or velocity and/or acceleration of a lower arm of the user, the determination means in communication with the controller for providing output data to the controller;
• and
• a set of electrodes for attachment to a limb of a human body, each electrode in communication with the controller for receiving an stimulation signal from the controller for applying an electrical stimulus based on the stimulation signal to a muscle of a user, wherein the controller is configured to:
• define a virtual environment;
• receive output data from the determination means to determine a first orientation of an upper arm of the user and a second orientation of a lower arm of the user;
• represent a virtual hand of the user in the virtual environment;
• represent a virtual object with a predefined mass in the virtual environment;
• and
• generate stimulation signals to simulate a force applied to the virtual hand by the virtual object,
• wherein the controller is configured to generate the stimulation signals such that the simulated force is determined based on the first and second orientations,
• wherein the controller has a training mode in which it is configured to:
• receive a plurality of electromyography data from one or more electrodes to generate a plurality of target data points;
• for each target data point, receive training data including data representative of a first orientation of an upper arm of the user, a second orientation of a lower arm of the user, and a mass held by the user;
• and
• apply a machine learning algorithm to the training and target data to provide a prediction algorithm for predicting muscle activation from the orientation of the upper and lower arms and mass held, and
• wherein the controller has a simulation mode in which the controller is configured to:
• define a virtual environment;
• represent a virtual hand of the user in the virtual environment;
• represent a virtual object with a predefined mass in the virtual environment;
• receive electromyography data from one or more of the electrodes;
• and
• predict a muscle activation from the orientation of the upper and lower arms and predefined mass using the prediction algorithm;
• and
• carry out the step of generating stimulation signals to simulate a force applied to the virtual hand, wherein the step comprises generating stimulation signals from the predicted muscle activation.