Robot work envelope

Robot working envelope must be securely guarded. 

The system is based on an XP Zymate laboratory robot controlled with a 10 slot System V controller using software version XP VI.S2. The system incorporates commerdaUy available hardware, as well as custom hardware. A schematic diagram of the system is shown in Fig. 6.11. The robotic arm and the peripheral laboratory stations that the robotic arm interacts with to perform the appHcation are positioned in a circular configuration. The GC/MS is located adjacent to the bench top, such that the injection valve is close to the sipper station. Peripheral items of hardware with which the robotic arm does not directly interact with are outside the working envelope. 

One of the most important features of a robot, which determines its work envelope (i.e. the maximum extent and reach of the robot) is its position in the robotic station, which can be fixed or variable. The former is used in circular robotic stations, which are typical of Zymark s Py technology. In this configuration, the robotic arm is in the centre of a circle and the different peripherals are included in a work envelope radius as removable pieces of a pie. The work envelope of the arm in this case is 360° and the radius equal to, or shorter than, the extent of the arm (see Fig. 10.3 A). 

The number of modules present in the work envelope of a robot arm varies with the number of tasks it is to perform in a given process. Some modules can be as complex as self-contained workstations. Although most of the modules required for the different steps of the process can be provided by either the arm s, or an alternative, manufacturer, some users design and construct their own modules, either because of the specificity of the task or with a view to reducing costs. A detailed discussion of such custom modules is obviously beyond the scope of this chapter. What follows is thus a brief description in relation to solid sample handling. 

The term work envelope is used to describe the normal reach a robot has, typically referring to industrial robots that are fixed in one place. The work envelope is important to know when designing a manufacturing process. It is also important to know for safety reasons. Safety zones around robots need to be clearly marked to prevent injury to humans and damage to the robot. 

A mobile arm in a robotic station is supported in a track that allows displacement of the arm in a length that varies, depending on the particular station, from 1 to 2 m. The capacity of the robotic station for locating peripherals in the work envelope of the arm can be expanded by using a more complex arm capable of operating on both sides of the track. 

A planar chromatography robot was proposed by Prosek in 1989. It consisted of a robotic arm (Figure 9) with 4 degrees of freedom on a rotating base. Its work envelope is composed of 4 tanks (1 for cleaning, 1 for development and 2 others for derivatization by dipping), a hot plate, a dryer, and a digital camera for the evaluation of the derivatized plate (28). An Apple He computer controls the whole system. 

Robot types variety of configurations, loading carrying capacity, working envelope, wrist degrees of freedom and accuracy/repeatability, e.g. revolute, polar, gantry and pendulum. 

The Puma robot has six degrees of freedom and has six revolute links to deliver a tool or maintain a position at any point in the space.The point has to lie within the working envelope. The first three links make up the main structure of the robot. The rest make up the wrist, which usually holds the part to be carried (see Fig. 1). The links are powered by DC servo motors. The robot is controlled by a programmable microcomputer. ... 

Due to limitations on the number of keys that can be provided on the teach pendant and it s size, teach pendants do not have as much functional control on the robot as a keyboard. However they provide the programmer a means of operating and programming the robot from different locations around the work envelope as may be necessary. The controls on a teach pendant can be functionally classified into following groups. 

Envelope—Space or maximum the volume of space encompassing the maximum designed movements of all robot parts including the end-effector, work piece, and attachments. 

PEL permissible exposure limit OSHA limit for employee exposure to chemicals (29 CFR 1910.1000) based on a time-weighted average of hours for a 40-hour work week Pendant any portable control device, including teach pendants, that permits an operator to control the robot from within the restricted envelope space of a robot Pendant control a means used by either the patient or the operator to control the drives that activate various bed functions attached to the bed by a cord Penetrating radiation any radiation that can penetrate the skin and reach internal organs and tissues... 

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