What a person needs if a robot is to prepare a meal for them.

Who needs a robot to prepare a meal for them?  According to AgeUK there are 1.6 million malnourished people in the UK. Many of them are elderly and cannot prepare an attractive meal for themselves, and possibly may not even be able to feed themselves. Cooking and feeding is very time consuming for a carer. If the carer is not family and provided by social services or a paid-for care organisation, then the problem begins. But many people have an independent spirit. They would rather struggle on than loose their pride and independence through going into a care home.  There is a vision that with a robotic device to help them they could remain sufficiently self-sufficient in the preparation of food, to remain at home rather than going into care. Perhaps it could be more  a domestic appliance that a robot, but what does it need to do? The person it serves will have one or more disabilities which may be either physical or cognitive or both and also possibly blind or deaf. Their needs vary very widely. One may be able to buy food and eat it unaided, but not be able to do the heating, while another may be able to do little but open their mouth. In general the user’s abilities are likely to be declining. To provide for all users it is therefore necessary that the robot is able to remove the meal from a fridge or freezer, heat it, place it in front of the user, and optionally spoon feed the user under their control. Other tasks such as offering drinks, snacks, drugs, or respiratory assistance are also possible but not considered here as they are comparatively straight forward.

Ready-meals

Ready-meals are the basic means by which many frail people feed themselves or are fed. They are attractive, available to satisfy nearly all tastes and needs, and cost far less than home cooked food when the cost of labour is included. A user, new to a robot aid, may already be eating ready-meals supplied regularly to the home, or purchased by themselves or by a carer.  Ready-meals therefore provide the most attractive basis for the robotic preparation of food and are the basis of these notes.

Ready-meals are available from retail outlets or from on-line delivery services. The needs of elderly people are met by a wide variety of attractive meals for both general needs and specialised dietary needs, including pureed meals. The main supplier to this market is Apetito AG who deliver their products both hot as meals-on-wheels through social services, and frozen under the brand name ‘Wiltshire farm foods’. Apetito is a German company and supply over 50 million meals a month to this market internationally.
Ready meals are supplied packaged in plastic trays, often with internal divisions separating for instance meat and vegetables. The trays are vacuum formed from thin sheet CPET plastic and come in a wide variety of shapes and sizes. Usually one meal supplier uses only a small range of trays. The meal tray is covered with a transparent plastic foil which is removed after the meal has been heated.food_trays_ready_meals

The tray presents three problems to robotic preparation of the meal. 1. The tray softens when hot and often has no opposed surfaces suitable for a robot to grip. 2. When the tray is removed from the oven it has a random orientation due to its rotation in the oven, but it will need reorienting if the tray has internal divisions (most main meals do) which determine in which direction the meal is to be spooned. The user may also be blind. 3. The foil cover must be removed which requires gripping a small foil flap in contact with a corner of the tray and pulling hard.

These problems are completely solved by using a meal carrier, which is a plate with an apeture in which the meal can be secured. Having a rigid rim, the plate makes the meal easy to grip and move. Ratchet teeth on its circular edge make it easy for the robot to nudge the meal into the correct rotational orientation. To remove the foil cover the plate provides a link that can be secured to the cover with a snap fastener, and which has a small strong magnet that the robot can attract to pull the cover off the meal.

Space

Elderly people often live in accommodation of limited size, however a short length of worktop or a table-top are very likely to be available on which can be placed the freezer, oven, robot, and the meal being eaten. The standard worktop is 60cm wide. Worktop freezers and compact microwave ovens fit on this surface and are cheap (< £100) so a pair may be purchased to suit the needs of the robot.

The layout of the items on the worktop needs to be compact, and must also avoid the possibility of contact between robot and user. It must allow the user, who may be immobile, to see into the appliances in order that he/she can retain as much control and dignity as possible. There is only one layout that meets these needs which is shown in the video. The appliances face each other, angled outward for visibility, and with the robot located between them. The geometry may be optimised to minimise the necessary length of the robot arm. In the video a template board defines the positions of the appliances and the robot through dowels that fit the appliances. Then these relatively light devices cannot roam from their preferred positions under vibration.

User interface

The way the user informs the robot of his/her needs will vary widely depending on the ability and the inclination of the user. As a minimum, commands to choose a particular meal, and to initiate the offering of a spoonful of food seem necessary. At the other extreme the user might wish to have full control over the robot motion. In practice, something in-between will be usual. The technology by which the command is given must be determined by the user. Technology to use the voice is now readily available through the mobile and the cloud, and seems likely to be favourite. At the other extreme the TV remote, which is used in the video, is cheap and convenient.

Summary

These needs taken together defined the design of the robot, the control software, the meal carrier and the arrangement of the components shown in the video.

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