The purpose of a robotic gripper is to effectively manipulate and grasp objects.
First of all, the system for gripping must be chosen. Such as two or more finger grippers, parallel jaw grippers, suction grippers and other types. Some grippers are designed for only specific types of objects, which makes the design easier.
Let’s list some key factors to consider:
Gripping force. This should be balanced at each instant and position, in order to be sufficient to hold and manipulate the object but not too much, in order to avoid damage. Dealing with delicate objects is especially a challenge.
Sensors: It is important to get feedback from the object being manipulated in order to manipulate it the desired way. Tactile force and proximity sensors are used.
Control: The control algorithm gets feedback from sensors, and controls the gripping mechanism accordingly, by adjusting the position of the grippers and the force applied by them at each position. Getting feedback and controlling grippers is a loop that constantly become each other’s input.
Actuation system: Based on the chosen gripper system, proper actuation method must be used. Hydraulic, pneumatic, electric and even shape memory alloys are the most common. Speed of manipulation, power usage, accuracy, ease of control are all determining factors here.
Range of motion: The range and size of expected / required manipulation needed is another major criteria. The wider the range of motion and size, the more complex the gripper system and the control algorithm gets.
Operating Environment: This is also a consideration if factors that will affect the operation of grippers, or surrounding items that will be affected as a result if gripper operation exist.
Materials: Strength, stiffness, durability, smoothness/roughness, weight of the gripper materials are considered. The materials must also be compatible for the target range of tasks and the geometric and physical properties of the objects to be handled. Adequate friction between the grippers and handled objects must be ensured. To maximize ease of actuation and minimize power consumption, lightweight materials are preferred unless there is a need for high mass grippers.
Adaptability: The ability to adapt to unexpected irregularities is a desirable feature, which increases the complexity of the system and control.
Connectivity: The gripper connections to robot arm or other surfaces should be as simple as possible and the value of gripper will increase as its ease of connection with different interfaces increase.
Safety: For a safe operation, measures such as impact detection, emergency stop, soft surfaces, should be implemented.
And as always, cost and ease of design, manufacturing and maintenance must be a key criteria.