ST Robotics

History

In 1981, David Sands formed the company Intelligent Artefacts which was based in Cambridge, England. One of its products was educational robot arms. The arms were programmed in the programming language BASIC and would run on any of the popular makes of computers of the time such as Apple (Apple II series), Acorn Electron, Atari, BBC Micro or the Commodore Pet. The robot competed with others in that market like the Armdroid. As the language Forth became available on these computers, Sands wrote the first version of RoboForth which enabled the robots to run and respond far faster. A version of RoboForth was also written for Armdroid.

In 1982, Intelligent Artefacts was closed down and a new company formed, also in Cambridge, called Cyber Robotics who sold a redesigned arm known as the Cyber 310. The Cyber 310 had a 5 degrees of freedom (DOF) ability. Hundreds of them were sold around the world between 1981 and 1987. The robot arm was adopted in 1987 by Mike Topping as the basis for the Handy 1, a robotic helper for the severely disabled. Cyber Robotics was bought by the Bibby Corporation in 1982 and it was eventually closed due to lack of sales.

During the period that Intelligent Artifacts was in operation, many inquiries were received for more serious and professional uses of robot arms for which the Cyber 310 was not suitable. This alerted David Sands to the potential for manufacturing a bench–top robot arm series, some of which already existed, notably the Zymark.

Sands Technology was formed in 1985. The company began to manufacture robot arms, such as the R12 Mk1, R15 and R16, which were used in applications from laboratory work in DNA processing to decommissioning nuclear reactors. In 1989, David Sands met Mathew Monforte in New Jersey and the pair decided to expand the company for the American market in 1991 and Sands Technology International was incorporated in New Jersey in 1992. The less personal pseudonym of ST Robotics was coined in 1997 under which both companies now trade. Also in 1992 Sands Technology formed one of the first joint venture companies with the USSR under Perestroika with the formation of Association Robot in Ekaterinburg, now dormant.

Technology

ST Robotics uses technology which is based on hybrid stepping motors as opposed to the more usual DC servo motors. For some years the technology had problems from lack of power and motor resonance. These problems were solved with the advent of rare–earth hybrid motors, high voltage micro-stepping drives and incremental encoder feedback. The robots calibrate themselves by driving each axis slowly to a target sensed by a proximity detector. Incremental optical encoders then track along with the motors to check for errors. This is called closed loop control which differs from servo control in that the stepping motors run essentially an open loop — the loop is only closed at the end of each movement of the arm. ST’s latest arm, the R12 Mk2, has the encoders only as an option.

The ST robot controller uses two processors: one to run the embedded RoboForth programming language and a digital signal processor (DSP) to control the motors. The DSP is able to control all axes collectively with individual axes ramping up or down as necessary for a compound motion. At the same time it reads back the encoders data and passes this information to the CPU which also uses the DSP's timers. RobWin is a GUI project manager for PC to create and edit projects and save them on disk but RoboForth, the user's program and all data are saved in flash memory in the controller.