Imagine an electric motor roughly the size of an ant, but 1,000 times as strong. Then, imagine that it moves like an ant, despite being constructed in one solid piece. The motor can actually “walk” using two pair of legs creating a synchronized step-by-step motion. The walking motion creates force used to move an object or to move the motor itself.
What is obvious in nature is not necessarily as obvious to an electric motor. The following animation demonstrates the walking-drive concept.
Piezo LEGS® Animation
Cost Effective Simplicity
The Piezo LEGS® rotational motor uses Piezo LEGS® Elements to create motion. Each Piezo LEGS® Elements consists of multiple bimorph actuators co-sintered into a single body with four movable legs made out of ceramic “muscles.” In other words, the Piezo LEGS® Element has only one part. This simple design makes Piezo LEGS® Elements easy to produce cost effectively in large quantities with a high degree of precision.
Piezo LEGS® Elements “muscles” create motion with no need for gears or mechanical transmission. A conventional electric motor requires a rotor, stator, ball bearings etc. to create rotational motion. To achieve smooth slow speeds and increase the system’s overall resolution, many rotary motors use a gearbox. While the gearbox may solve design challenges, it typically increases the system complexity, amount of backlash, and manufacturing costs. In the case of brushless motors, the gearbox becomes the limiting factor in the system’s life expectancy. Unlike brushes, bearings, and gears, the leg material is virtually impossible to wear out.
With the Piezo LEGS®, you can design a cost-effective and reliable linear-motion system with a minimal number of components.
Accurate positioning means little without reliability. As one pair of legs remains engaged all the time, control of the system exists at all times. Even when de-energized, the legs remain engaged maintaining position until the system regains control. Resistant to wear-and-tear, the system should behave consistently during the usable life.
Amazing Speed Range
The motion dynamics are truly fascinating. With step resolution of a single microradian, a slow move translates to less than one revolution per week; however, the Piezo LEGS® rotational motor can still rotate up to a no load-speed of 20rpm.
Made to Your Specification
Flexibility in the design allows modifications to adapt the motor’s properties and performance to suit your application or product. This saves you time and money as you do not have to change your product to fit the motor. The combination of power, speed, precision, and the compact format makes the Piezo LEGS® Element a great choice while the cost makes it an excellent value.
The Piezo LEGS® motor comes in different versions including models for linear motion, vacuum compatibility, and nonmagnetic applications as well as different sizes from one to several hundred Newtons of pulling force. The linear stage shown to the right shows how the Piezo LEGS® Element incorporates into a familiar design.
We look forward to working with you throughout the design process.
Simple Control Electronics
The drive electronics required to drive and control the Piezo LEGS® rotational motor are no more complicated than those required for stepper motors. Applying voltage to the ceramic “muscles” synchronizes movement of each pair of legs, enabling them to rotate the output shaft clockwise and counter clockwise.
The unique design of Piezo LEGS® rotational motor makes the motor walk in a circle. By bending a pair of legs, the motor can move with microradian precision or one ten millionth of a turn! By taking several thousand steps per second, Piezo LEGS® rotational motor can reach a no-load speed of 20rpm.
By controlling the movement pattern of the legs more precisely, one can also adapt and optimize the motor’s properties to different types of applications.