IEN: What are the major concerns facing motion technology, and how can they be addressed?
Godbole: The major concerns facing motion technology are:
- Drive to increase performance
- The ability to create precise networked motion
- Size constraints
- Persistent cost pressures
- Energy efficiency.
Motion Control designers are squeezing more out of less by using advanced commutation strategies for brushless servo motors, such as replacing trapezoidal commutation with closed current loops and field-oriented control (FOC).
This eliminates one of the major sources of torque ripple, which translates as a control model uncertainty to the control system designer. Traditionally this solution has been deemed unacceptably complex for servo drives, and the bandwidth of the field-oriented control has been limited. The principal limitation has been the need for considerable computational capability needed to implement the field-oriented control.
The addition of devices such as TI''s C2000 DSP-based controllers has changed this equation to where the designer need not compromise on the control quality just to implement the control in real time or meet cost goals.
Another concern is to increase energy efficiency by choosing control strategies that get the most torque per ampere from the motor, and create less heat that must be dissipated. In many applications, a better control strategy leads to elimination of mechanical components, and leads to smaller system size and system cost reduction.
Since powerful DSP controllers run the control law in a fraction of the time and cycles it takes a simple microprocessor to do so, they can also dedicate cycles to running other software, which can absorb functions such as motion profiles into the same controller.
The bottom line is that designers are using mathematical processing power to their advantage, by using powerful math engines to run their computer intensive algorithms. TI DSP controllers are enabling them, by providing leading edge performance.
IEN: What innovations are in store for users of drives, motors, servers, control systems, software, miniaturization, customization, and other motion-related technologies?
Godbole: Advancement in control strategies leads to improvement in the performance, efficiency, cost, noise levels, and operating life of controlled electric motors.
From a user point of view, users will see their equipment become smaller and more efficient.
Also, programmable processors will offer users features such as smart motion control systems, with any number of features ranging from multiple language support for industrial drives, to the ability to customize their drives to their exact specifications.
Also, the capability to create smart motor controllers will lead to the ability for designers to integrate more functions such as power factor correction into their equipment, which means that system integrators need solve only much reduced EMI problems.
As another example, automotive engineers are creating smoother and lighter power steering, and at the same time improving fuel economy using digital signal controllers. Electronic power steering replaces the hydraulic system with electronic motors. This transition is helping accomplish goals such as reduction in overall weight of the car, and consequent improvement in the fuel efficiencies and costs. These high performance and reliable motors must provide fast and accurate response and require sophisticated algorithms to control. DSP-based controllers are ideally suited for this application and manufacturers benefit from reduced parts count, lower vehicle weight, elimination of drag on the engine, and increased fuel economy.
IEN: How much progress has been made in preventing software and hardware debugging issues? Installation challenges?
Godbole: For designers of motion control systems looking to implement control systems, one of the traditional areas of concern has been implementing arithmetic in a fixed-point domain. To this end, innovations such as IQMath from Texas Instruments simplify and dramatically shorten their development cycle.
Extremely efficient C compilers allow developers to create object code nearly as compact as native assembly, yielding excellent real-time performance.