CONTROL SYSTEM DESIGN - Pacific Watercraft Group

THE CHALLENGE

Pacific Watercraft Group (PWG) came to ControlTek with an idea for the next generation of their SOLO Personal Ski Machine. The current product used a wired configuration, implemented via a proprietary tow rope and handle connecting the controls to the boat. PWG was ready to update to a new wireless design so water skiers could use their own favorite ropes and handles; basically, the ski machine would become a remote-controlled boat.

ControlTek was asked to design the control system for the boat. Safety of the product is critical, so the system needs to be fail-safe. The product roadmap is long, so the system also has to be capable of evolving into many future versions.

Pre-sales were already in process with promised delivery schedules. The timeline was very short for a project of this scope, and would have to be managed exceedingly well.

OUR SOLUTION

First things first. A dedicated Project Manager was assigned to actively drive the project to success. Meetings began immediately to define requirements and specifications, which are essential to good product design. There is no room in the schedule for numerous iterations.

Five modules and a wiring harness are required to implement the design. A Main Control Unit (MCU), Control Pad/Display Module (CDM), Handle Module, Skier Module and an Auxiliary Stop remote will comprise the control system. The MCU & CDM are attached to the boat, while the other three are remote from the craft and wirelessly connected to the CDM.

Wireless Functionality

Bluetooth Low Energy was selected for the wireless functionality. GPS is built in to the CDM, Handle and Skier modules so relative positioning between the modules is known. This allows for skier down detection and future features such as auto return to skier and course mapping.

Control System Interface

The MCU is the control system interface to the rest of the watercraft, incorporating protection circuitry for overcurrent, load dump and reverse polarity while providing conditioned power for the rest of the system. Motor controls are provided for steering and acceleration actuators, along with two spares for future expansion.

The CDM is the brains of the system, sending control signals to the MCU, communicating to the wireless modules and providing web server access for firmware updates, diagnostic data downloads and smart device access to the boat. A 5” sunlight readable LCD is included for the user interface.

The skier, handle and auxiliary stop modules are highly visible and will float in case they become separated. All three also contain rechargeable lithium polymer batteries for up to 8 hours of operation from a single charge. Charging ports are conveniently provided within the accessory stowage compartment. Tactile feedback membrane keypads are used for all buttons. All modules are IP67 rated to prevent issues with water, sand and fuel contact/immersion.

THE RESULTS

The project is still in process but check back for updates along the way!