Automated Guided Vehicles (AGVs) and Autonomous Mobile Robots (AMRs) are two segments of robots now being increasingly used in production facilities and warehouses across the globe. AGVs navigate along a predetermined path across a facility, performing transportation tasks and so on, while AMRs autonomously navigate across the premises performing more complex tasks. Whether it’s an AGV or an AMR, tasks assigned to them boost productivity. This is because they can perform repetitive material handling tasks without many breaks (even for three shifts if need be) as would be required by manual workers. But it’s not as if these robots do not have to take a break at all. Operated primarily on electric batteries, AGVs and AMRs stop to recharge themselves at charging stations. But what if we were to make the charging process more process and time-efficient?

AGVs and AMRs batteries are charged manually. This ought to consume time in manually attaching cables to the robot in addition to the time required to charge it. Multi-faceted this concern may be, nonetheless, there is room for increasing productivity in terms of charging. One may require more than needed AGVs/AMRs such that while one set is running around, the other gets charged.

Wireless Charging is a Step Towards Productivity of AGVs and AMRs

Several solutions have been suggested to counter the inefficiencies in charging AGVs and AMRs: designing the optimal use of these robots such that the productivity (downtime/standby-time) of production facilities does not drop drastically, determining the most time-efficient route to charging stations and so on. Likewise, they have developed algorithms that help schedule charging sessions during off-peak hours or times when AGVs or AMRs are not in active use (not loading or unloading times). Similarly, implementing dynamic routing algorithms that consider battery levels and charging station availability when planning vehicle paths is another way to optimize the charging of AGVs and AMRs.

However, the industry has realized that the potential resolution lies in changing the charging method-Wireless Charging. Unlike traditional charging methods that require manual intervention or physical connections, wireless charging offers efficient power transfer to these robotic devices. By utilizing electromagnetic fields, inductive coupling or resonant coupling, AGVs and AMRs can recharge their batteries automatically while in operation (dynamic wireless charging) or during scheduled downtime (quasi-dynamic wireless charging), eliminating the requirement for human intervention and optimizing workflow efficiency. Wireless charging systems are also a step towards full automation of factory operations, especially those requiring a clean environment.

Technologies to wirelessly charge AGVs and AMRs

Near-field wireless charging technologies, such as low-frequency or high-frequency, inductive or magnetic resonance charging are often favoured over their far-field counterparts. Resonance coupling which involves transferring power between coils tuned to resonate at the same frequency holds promise. It implies efficient energy transfer even with slight misalignment between the charging pad and the receiving device. Electromagnetic induction, on the other hand, relies on generating a varying magnetic field to induce an electric current in a receiving coil, providing high efficiency but requiring more precise alignment.

While the near-field wireless charging technologies have their merits in realising a fully automated charging system for AGVs and AMRs, it is not to say that each technology is not accompanied by its own set of concerns.

Inductive Charging Calls for Precise Alignment of the WPT Receiver and Transmitter

Inductive chargers are efficient and reliable since they do not require physical contact with the robot to charge it, but the robots need to precisely align themselves with the charger for maximum efficiency in charging. Here, AGVs can be preprogrammed for precise alignment but such can’t be the case with AMRs which are more autonomous with their tasks and the path they decide to take to accomplish them. The conventional resolution for the alignment issues with inductive charging and even magnetic coupling is to tweak the charging station or the transmitter to allow for more charging efficiency.

But recent technological developments are pointing in the opposite direction: Incorporating dual coils inside the AGV itself. Some recent research though crude suggests that AGVs with dual coils within them could be more tolerant to misalignments while charging.

Integration of dual coils within AGVs enhances their overall autonomy and operational resilience. AGVs equipped with this technology can independently navigate to charging stations, initiate charging sessions, and adapt their positioning, as needed, to ensure reliable and efficient charging without human intervention. While still in the early stages of development, research into dual-coil AGVs represents a promising direction for overcoming the limitations of traditional inductive charging methods.

Interference and Range are Prevalent Hurdles too

The major drawback of inductive charging of AGVs and AMRs is the limited range of distance the wireless charging technology allows. Allowing only a range of up to 4cm, most inductive charging systems could render alignment and charging of multiple AGVs simultaneously more complex than it has to be. The industry could focus on devising innovative solutions to overcome the range and alignment challenges of inductive charging which is more power efficient than its alternatives.

The Resonant Inductive Coupling method of charging is relatively better in terms of the range of distance permitting charging. But the trade-off here is with the efficiency of charging. Capacitative Coupling charging might seem preferable here, but it introduces a more prevalent concern – interference. Capacitive coupling relies on the electric field between two electrodes, one in the charger and the other in the device that is being charged. This electric field can be influenced by nearby conductive or dielectric materials. As a result, interference can occur from objects or materials that alter the electric field, such as metal surfaces or even human bodies. These interferences can disrupt the charging process or reduce efficiency.

Interference is a noteworthy challenge while wirelessly charging via capacitative coupling but this doesn’t mean it is a challenge restricted to the latter. Interference can be in the inductive charging solution too: arising from external magnetic fields generated by other electronic devices, power lines, or even nearby metal structures. These external magnetic fields can distort the charging field, leading to reduced efficiency or even complete disruption of charging. This concern can be more relevant to facilities which use equipment generating strong electromagnetic fields which could not only intervene in the charging process but also damage the AGVs and AMRs circulating within the facilities’ premises.

Summary

The increasing adoption of Automated Guided Vehicles (AGVs) and Autonomous Mobile Robots (AMRs) in industrial settings has boosted productivity, yet the manual charging process presents a bottleneck. Wireless charging technologies, particularly near-field methods like inductive or magnetic resonance charging, offer a solution by enabling automatic recharging without human intervention. However, challenges such as precise alignment requirements, interference from external factors, and limited charging ranges persist. Recent developments, like integrating dual coils within AGVs to enhance alignment tolerance, show promise in overcoming these hurdles. Despite these challenges, wireless charging holds significant potential to streamline operations and further automate factory environments, but continued innovation and refinement are necessary for widespread implementation and efficiency optimization.

WAWT, through its comprehensive research across the wireless power and AGV/AMR industry ecosystem, has already witnessed the introduction of some innovative wireless power solutions being developed and many thousands being deployed by innovative wireless power technology companies in the market. The future looks bright for such AGV/AMR applications and industrial and factory workplaces. WAWT also believes that the wireless power market has not been too successful in showcasing the real benefits associated with the adoption of wireless charging-enabled AGV/AMR and thus considered as a cost feature rather than a value feature, and considered an expenditure rather than an investment for increasing return over investment (RoI).

About Wired and Wireless Technologies (WAWT)

Wired and Wireless Technologies (WAWT), through its comprehensive research data and insights and market intelligence on the wireless power market titled ‘Wireless Power Intelligence Service’, covers various types of wireless power technology solutions using different frequency levels – be it inductive, resonance, NFC, RF, or infrared-based. WAWT monitors the use of various types of wireless power solutions developed and adopted across 30+ different types of application markets across automotive, consumer, computing, wearables, hearables, medical/healthcare, smart home, industrial, robotics, retail, infrastructure, and other sectors. 

Do reach out to our subject matter experts (SMEs) by emailing [email protected] and following our LinkedIn page (WAWT) for the latest market estimates and forecasts, trends, insights and updates on wireless power/charging and allied technologies.