2011 University of the Witwatersrand – Automated Restaurant

A design submitted by WITS students, Mduduzi Prince Masuku, Lefa Matape Madire, Meshi Lucas Hamese and David Ndeveelo achieved a highly respected third place in the 2011 PneuDrive Challenge. The students, from the WITS school of Mechanical, Industrial, and Aeronautical Engineering suggested a design composed of sub-systems that automatically deliver orders from the kitchen to patrons at their designated tables in the restaurant.
The purpose of a restaurant is to generate business by bringing together the ambience or experience of the establishment, the culinary skills of chefs and the expectations of patrons. These three elements can easily have synergy when trading hours are quiet, but inefficiencies and compromises do occur during peak periods.
More staff could be employed to address peak hour demand, but besides increased operational costs, this approach may have some unforeseen consequences, for example:
•    Negative impact on the performance of existing waitrons
•    “Kill”’ the ambiance of the restaurant because of “overcrowding” on the shop floor
•    Increase staff and operational costs.
However, by considering a mechatronic solution that promises to eliminate the number of waitrons, and incorporating an automated delivery system, restaurants do have other alternatives to improve and optimise the delivery of meals and therefore the experience of their patrons.

Link to video of the Automated Restaurant application: YouTube

Competing Students: Mduduzi Prince Masuku, Lefa Matape Madire, Meshi Lucas Hamese, David Ndeveelo

Click here to download a PDF copy of the technical and design summary.

The Environment

Restaurants all over the world.

The Problem

Because of possible limitations of a restaurants environment and its waitrons, inefficiencies can occur during peak hours of operation.

The Proposed Solution

The Automated Restaurant proposes to replace the waitron and deliver food by means of automated mechatronic system that delivers meals from the kitchen to customer’s table.

The Market

There is no special market. Each restaurant can choose to use and install the proposed system.

How It Improves on Current Systems

The machine will improve and optimize the efficiency and performance of restaurants. Moreover it will decrease staff costs. The machine will also be able to operate without typical staff problems and required staff breaks.

The Cost

The design suggests that the raw material and bought-out parts cost R300 000. This amount excludes on-site assembly and installation costs as well as overhead costs. Building and renovation costs were not considered in the budget either.

Unique Features

Although other “automated restaurants” do exist, the efficient use of space is unique in this design, as most of the mechanical components are isolated from the dining floor.

The main objective of the design was to replicate the tasks of a waitron, with food that is prepared in the kitchen being conveyed by a mechanical system to the dining table.

When the chef indicates to the system that the meal is ready, the prepared food is placed into the Food-Box which is used to deliver the order to the customer’s table. A lifting mechanism is lowered to the basement where the Food-Box is loaded onto the cart. This loading and lifting mechanism is managed by a “Translating Robot”. After the lifting mechanism has finished loading, the Food-Box is moved to the dining table. When underneath the table, the lifting mechanism uses a FESTO Inductive Proximity Sensor to trigger a signal that opens the “delivery door” on the table.

The concept of a lifting mechanism was proposed in the design of this automated restaurant because it was considered cost effective and energy efficient.

The lifting mechanism is essentially a raising and lowering platform with electrical and mechanical drive systems.

Safety and adaptive features such as guides to prevent excessive lateral movement during lifting and lowering also form part of the design.

The overall lift mechanism employs pulley techniques which are important for low energy consumption. The mechanical advantage of this system is that the output force (weight loaded) is half the input force (pulling force).

The conveying mechanisms proposed for this automated restaurant features a flexible rail that should be able to reach any table, regardless of complex table mapping requirements.
The chosen concept was also designed to maximise energy efficiency.

The table tops of this automated restaurant have been designed to have table-top sliders that open automatically when the Food-Box is lifted to the correct position, and close when the Food-Box is lowered away from the table.
The sliders are designed to be moved by a FESTO Linear Actuator that operates by converting “motor rotation motion” into “linear motion”. This is achieved by using a power screw connection.
The advantage of using FESTO Linear Actuator was that it can work with both “servo” and “stepper” motors. This makes the selection of the type of control system easier because there is no need to change the linear actuator for a prescribed control system. For example,  an “open loop system” that uses a stepper motor could be changed for a “closed loop system” that uses a servo motor.

The Food-Box is the main interface between the restaurant customer and the automated restaurant.The Food-Box is designed to contain two meal holders that open up on opposite sides. Each meal holder has two levels of trays, one level carries the plates with the food served, and the other level carries the drinks and cutlery.
Each meal holder is lifted by a FESTO Spindle Screw Actuator, and is driven by a medium size motor with an encoder. The food trays are opened using a FESTO Power Screw Mechanism.

An interesting component in this automated restaurant is the “holder” that houses the FESTO motor. It was designed so that it holds the motor in such a way that there would be no axial loads between the motor and the linear actuator spindle.

The Translator Robot, a sub-component of the system that is designed to transfer the Food-Box from the cart to the lifting mechanism of the automated restaurant, picks up the tray of food from the cart, moves it along the rail and places it on top of the lifting mechanism.
The design stipulates that a single translator can cater for three tables in one row. It is designed to “translate” from “side-to-side” and to serve tables according to sensor signal inputs received from tables as the moving cart approaches the designated table. The Translator Robot also slides forward and backwards to lift the food carrier up so that the container can be transported to the lifting mechanism. The forks, or arms of the transaltor emchanism also swing in and out providing reaching capabilities that allow for the sliding of the tray to the food carrier and back.     
The system uses two FESTO double acting pneumatic cylinders . One cylinder pushes the slider back and forth, the other pulls the food up and down. The extended movement of the forks is provided by the SEW Eurodrive MoviGear gearbox.