Because more collaboration between robots and humans is required, the definition of vertically articulated robots has shifted from working in a collaborative workspace to collaborative operations. In a collaborative workspace, there is no direct collaboration between the robot and the human, whereas collaborative operations require direct cooperation between the two.
In collaborative operations, cobots support human workers by performing repetitive tasks and ensuring high-quality products in often space-constrained environments. By leaving more repetitive tasks to robots, workers can focus on other, more important tasks on the production line, such as fine-tuning and optical inspection of subsystems.
Importantly, collaborative robots must be cost-optimized and have size and safety assessment capabilities when installed in the factory floor, as well as features that help ensure employee safety.
When upgrading compact factory floors with robots, it is sometimes impossible to create safety fences or zones around each robot while still maintaining productivity. Collaborative robots with built-in safety eliminate the need for this additional safety zone, making it much easier to integrate Cobots into existing workflows and improve quality and output (Figure 1 ).
Figure 1. Cobot is typically used in factory processing.
In order to achieve collaborative operation, collaborative robots must include the following functions:
Parking monitoring with security level
Speed and separation monitoring
Power and force limitations
Safety-related functions can be achieved by complying with the International Organization for Standardization ( ISO ) 10218-1 : 2011 , technical revision ISO/TS 15066 , and American National Standards Institute / Robotics Industry Association R15.06 2012 standards.
Collaborative robots are typically used to move weights (payloads) ranging from 15 kg to 30 kg. This weight is usually the force required for the collaborative robot to perform its work tasks. This variation in payload also necessitates a rethinking of the entire architecture of how the robot works, which in turn affects the robot's size and weight. Changes in architecture often result in a shift from a centralized to a distributed hardware architecture.
Centralized systems typically group the main functions (logic control, motion control and coordination, motor control, and sensor processing) together, usually in a large cabinet some distance from the operator. Extensive wiring networks handle power supply, feedback, and control for the motors and sensors.
In distributed systems, some of these functions are moved to the robot cabinet, arms and joints, or even embedded in the motor itself. Figure 2 shows a simplified example of a distributed system.
Figure 2. Distributed robot systems provide more flexible support in multi-robot environments.
When distributing electronic content, remember that the environment in which electronic devices are used differs from that of centralized systems. This difference necessitates redesigning electronic devices and may even require redeveloping parts of the system.
Defining certain subsystems early in the redevelopment process can ensure a smooth development cycle. These subsystems may include:
Low-latency real-time motor control and sensor feedback enable smooth, precise, and efficient movement of the robotic arm.
A communication bridge between the internal and external interfaces of a collaborative program.
Any required functional safety and security features help ensure user safety and product certification.
The Texas Instruments ( TI ) C2000 microcontroller enables low-latency real-time control and sensor feedback while still providing smooth, precise, and efficient motion through the use of hardware accelerators and highly flexible and integrated peripherals. The processor is the heart of a collaborative robot, but without analog circuitry surrounding it, it would be impossible for a collaborative robot system to operate with the necessary performance and functionality.
Optimized mixed-signal semiconductors offer flexibility in interfacing with various rotating sensors to sense analog current and voltage in different ways (or interface with sensors), processing feedback and calculating control responses in the shortest possible time to generate a range of precise outputs. This enables proper control of the motor - inverter power electronics.
Part of the design work involved ensuring that the analog components could provide the collaborative robot with the necessary accuracy, low latency, and efficiency requirements. System performance could be maintained even in noisy factory environments, taking into account different interfaces and sensing technologies. These architectural considerations would also influence the collaborative robot's power architecture, which must provide noiseless point-of-load power rails to supply high-precision analog and processor components.
Communication bridges in collaborative robots need to address low-latency, low-jitter sharing of information from sensors, distributed controllers, system controllers, end effectors (tools), and any higher levels of coordinated automation. For example, TI 's Sitara processors can use multiple coprocessors to meet these requirements, providing flexible deterministic, low-latency, low-jitter communication interfaces. These interfaces can support proprietary and standard real-time protocols using the same pins on the processor. Numerous interface options exist, requiring trade-offs between speed, reliable communication range, robustness, system security, and overall cost.
in conclusion
Collaborative robots are highly complex systems, presenting numerous design challenges in mechatronics, safety and functionality, and electrical aspects. You need to address these challenges and make several functional decisions before you can use the working system.
Embedded technology offers a wide range of products and designs that can help solve robotic problems and enable the development of intelligent, autonomous, and collaborative robots, leveraging all the different technological aspects of robotic systems.
