Develpopment of the Washbot Robotic Arm by Letsky Innovations a Product Design Firm

Washbot Phase 1: Design

Have you ever been in a situation where you want to clean your roof, you don’t own a ladder and you wouldn’t get on one because you are terrified of heights? Do you own a pressure washing business and want to lower your insurance bills?  Well, our client came to our product design firm to engineer a solution for this, and we did – The Washbot!

Washbot is a remote controlled robotic platform designed to perform operations such as pressure washing, sandblasting and painting remotely. How? You ask? The head of the robotic arm can be changed to your tool preference for different jobs. The tip of the arm is fitted with a pressure nozzle supplying water at 1500PSI @ 3.5 gallons/minute. The arm reaches 50 feet when unfolded.

Characteristics of the Washbot

Once our product design firm developed the requirements brief, it begun working on a concept that would meet the main characteristics that the client required. These were:

  • The arm should reach surfaces placed 50 feet high
  • The tip should deliver water pressures 1500 psi at 3.5 gallons per minute
  • The tip should always remain 6 inches away from the surface
  • The arm should work with third party items such as water tanks, pressure pumps, etc.
  • The structure should be stiff but light
  • The mechanism that drives the arm up and down should be built from ground up considering cost, user experience and the ability to manufacture it.
  • The base should have stabilizers so that the arm can be extended fully and safely.


With the requirements in mind, we immediately started developing the first prototype of the product. We designed a 4 segment arm that uses motorized articulations to extend up to 50 feet. The last segment was designed as a motorized telescopic system so the tip can slide over the roof surface while spraying water.


The segments and motors were arranged as follows:

  • Four truss segments of the arm made of welded pipes with efficiently calculated geometry. These had two main functions. To power the joints and upper telescopic segment and segments of the Washbot arm using a structure for the pneumatic hoses and cables
  • Four joints housing a pneumatic motor that can move the entire weight of the arm. Magnetic safety brakes were features so as to lock the arm in position if power drops thus preventing it from collapsing.
  • The telescopic segment was powered by a motor through a set of spools, steel wires and pulleys.
  • One segment centered on an axis to ensure the arm is locked on axis while allowing for longitudinal movement

Schematics of the proposed initial design were drawn up and sent to the client for review and approval a standard practice at our product design firm. The next phase, once approved, was to improve the design for optimal performance. More covered in the next Blog Post.

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